-Drug Addict Icon-There’s a well known statistic that Facebook loves to tout publicly: 50 percent of active Facebook users return to the site daily. It’s an impressive statistic that few application developers have been able to duplicate. Actually, only one application has been able to reach Facebook’s impressive engagement level but many others have come extremely close. As you will see, these applications are indeed the most addictive applications on Facebook.

We’ve gone through the process of determining which Facebook applications are in fact the most engaging applications on Facebook. So how do we determine engagement? Currently we measure engagement as daily active users (DAUs) divided by monthly active users (MAUs). This metric measures what percentage of an application’s total monthly user base returns to the application daily.

I will soon make this metric public and sortable via our Facebook application statistics tool. For now, you can scan over the 25 applications listed below. I also follow-up at the end of this post with some general thoughts on this metric and what developers can learn from this list.

1. Slots – 52.02%

-Slots Icon-You may have not played Slots on Facebook before but around 70,000 people have played and a whopping 52.02 percent of those users return every single day. There are two other games in the leaderboard which are part of this application’s “network”. You can play “Scratch and Win” (3rd most engaging application) and “Pull Tabs” (10th most engaging application), and use the tokens that you’ve won from those applications to bet on slots.

While it may not be the most popular application on Facebook, the developers behind this game are most definitely generating some decent cash flow through repeat users. Also, given that incentive based advertising is the most profitable thing on Facebook, owning a leading gambling application is not a bad position to be in. You can go play the application here.

2. Facebook for BlackBerry Smartphones – 48.9%

-Facebook for Blackberry Icon-It’s not surprising to find a Facebook owned application in this leaderboard considering that 50 percent of active Facebook users return to the site daily. If you have a BlackBerry, there’s a good chance that you’ve already installed this application. Out of the 3.5 million users that have installed the application, 1.7 million are using it daily.

While it’s not surprising to see a Facebook owned application rank so highly, it is somewhat surprising that Blackberry users are the most active mobile Facebook users so far. If you have a Blackberry and read this blog, you probably have already installed the Facebook for Blackberry application. If you haven’t, I seriously suggest you check it out.

3. Scratch and Win – 47.62%

-Scratch and Win Icon-Proving that gambling is a popular activity on Facebook, Scratch and Win comes in 3rd with 64,888 out of 136,000 monthly active users returning daily. Scratch applications have been around the Facebook platform since early on. Backstage, the company behind this application, is sitting on a pretty nice suite of gambling applications. When ranking applications for profitability, I would rank this company up near the top.

Despite having less than half a million monthly active users, a very large portion of their users are returning daily, and that is one of the most important factors when monitizing applications. If you are in to lottery tickets, go check out the Scratch and Win application.

4. Digsby – 47.3%

-Digsby Icon-Digsby is an extremely popular desktop instant messaging client and was one of the first, if not the first application to integrate Facebook chat. Unlike Meebo, who had their instant messaging support shut down, Digsby has remained functional since their launch. There is one problem with the application that I experienced which was that you would be kicked off of the web version of Facebook as soon as you logged into Digsby.

Regardless, out of the approximately 80,000 users that have taken advantage of the Facebook/Digsby integration, over 32,000 are logging in daily, oftentimes more.

5. Wordscraper – 42.1%

-Wordscraper Icon-When the Agarwalla brothers had Scrabulous shut down, it was one of the most buzzed about news stories among technology news sources. Today, the brothers still hold some of the most engaging applications on the Facebook platform including Wordscraper which ranks above both official Scrabble applications. It was a swift shift from Scrabulous to Wordscraper, and the brothers made enough changes to avoid a future law suit.

Now the brothers have the top ranking word games on the platform and they aren’t complaining. While the law suits brought much unnecessary attention to the brothers, the buzz helped attract attention to their new games. While they may have been temporarily knocked down, the brothers are truly masters at developing word games.

6. Facebook Toolbar for Firefox – 40.53%

-Facebook Firefox Toolbar Icon-It’s not surprising to see Facebook applications rank among the most engaging applications on Facebook. Perhaps it’s not even fair to include this in the list as desktop applications tend to receive a higher level of engagement. If you haven’t tried out the Facebook toolbar for Firefox, I suggest trying it out. It lets you know about new pokes, friend requests, messages, event invitations, and group invitations.

Then again if you have a ton of unopened messages and requests like I do, it may become a bit annoying to have the toolbar. If you are obsessive about cleaning out your requests though, this toolbar will come in handy.

7. Super Scratch Offs – 39.9%

-Super Scratch Offs Icon-Yes, another scratch off application. It appears that Facebook users are really in to gambling, or at least competing for reward points. This is the second most engaging scratch off game on Facebook and currently it has just under 140,000 monthly active users. Around 55,000 users return daily to see if they’ve won their daily scratch ticket. Clearly the developers of the scratch off games are laughing all the way to the bank as these users don’t seem to go away.

So you may be wondering what you can win by playing Super Scratch Offs. Virtual gifts! Yes, you heard that right. Users are returning every day to play Super Scratch Offs for the chance to purchase virtual gifts. It’s almost like a Chucky Cheese’s model or Dave and Busters, except in this game you can’t win any real candy.

8. Dungeons & Dragons: Tiny Adventures – 39.86%

-Dugeons & Drangons Logo-I bet you didn’t realize that there were some uber geeks on Facebook. Hasbro got creative on Facebook and their subsidiary Wizards of the Coast, launched the a Facebook version of Dungeons & Dragons. The game reminds me of the old choose your own adventure books in which your character had hit points and various other variables which determined the outcome of battles along the way.

These adventures have around 6 steps which is why the application is called “Tiny Adventures”. It’s a traditional fantasy game similar in some ways to Mob Wars and other strategy games on Facebook. This application is ultimately a big advertisement for Dungeons & Dragons but almost 30,000 users keep coming back every day. 23415053320

9. Egg Breaker – 39.85%

-Egg Breaker Icon-Egg Breaker is a game which continues to rise in popularity. Essentially it’s a new twist on the scratch off games. You click on eggs to break them and you can win gold, pieces of a star, virtual gifts, and points. Each day you are given a limited number of hammers to go and crack eggs in the game. Some eggs are harder to crack then others. You can also progress to new levels but I wasn’t completely clear about what triggered access to new levels.

Once you run out of hammers you can either wait a day or proceed to purchase more hammers with real money, gold that you’ve won in the game, by installing applications, or completing offers. So what can you buy with all of the gold that you won aside from new hammers? Virtual gifts of course!

10. Pull Tabs – 39.6%

-Pull Tabs Icon-By now you should be able to guess what type of game Pull Tabs is. It’s another lottery game but instead of scratching a ticket, you can pull off tabs on a ticket! Just like the other lottery games, you get to spend your winnings on virtual gifts. You can also send pull tab cards as gifts to other friends. One of the biggest incentives for playing the game is to get more credits to purchase pull tab tickets with higher payouts.

Many of the pull tab tickets are branded, including one which is branded for the movie iRobot. The application is well developed and it’s not surprising that this is one of the more popular “gambling” applications on Facebook.

11. Facebook for Palm – 39.1%

-Facebook for Palm Icon-I don’t really need to elaborate on this one. First of all I should add that Palm sucks :) If you are one of the few Palm enthusiasts though and you read this blog, there’s a good chance that you are one of the 115,000 people that have used this application in the past month. It appears that no matter what mobile device you prefer, Facebook tends to be one of the most popular applications. That’s not surprising considering that there are over 4 million daily Facebook mobile users.

As we highlighted last night, mobile is probably the fastest growing area (percentage wise) for Facebook despite the addition of over 450,000 new Facebook users each day. Anyways, if you are a Palm user, go check out the Facebook for Palm application.

12. Super Slot Machines – 38.8%

-Super Slots Icon-Are you serious, another gambling application? Yes, and we aren’t done with them yet. If you are the type of person to scratch off tickets then maybe you’ll enjoy playing slots. Just like all the other gambling games, the premise is the same. You play for tokens that you can in turn exchange for virtual gifts. Thankfully you don’t actually lose your tokens though.

You spend your credits for a chance to win more prize tokens. When I played the game I was one of the day’s big winners and I felt extremely proud about that fact. I walked away with a whopping 303 prize tokens after my first attempt. So if pull tickets are your type of game, go check out the Super Slot Machines application. 16154121637

13. Slot Machine Bandit – 38.7%

-Slot Bandit Icon-I swear this is the last gambling application! There’s really not much to say about this one. It’s pretty much the same thing as Super Slot Machines except the design isn’t as nice. There also doesn’t appear to be any fun sound effects which was a little disappointing. Also disappointing was that I didn’t win as much money as I did in Super Slot Machines.

If the developers of this application boost the odds a bit, I would guess more users would come back to play on a regular basis. Then again, the streaming notifications about other users winning the jackpot keeps you pulling on the slot machine handle. I won’t be coming back to this application but that’s not stopping over 26,000 people from returning to Slot Machine Bandit daily.

14. Parking Wars – 36.7%

-Parking Wars Icon-A&E Network must be happy that they decided to launch the Parking Wars application to promote the Parking Wars television show. While I don’t remember the television show, I definitely remember when this game was released over one year ago! More then one year later, the application attracts close to 110,000 people daily.

It’s an impressive feat which is hard to duplicate. It’s rare that branded Facebook applications succeed as much as this one. Thanks to the right timing and a good development team, Parking Wars remains to be one of the most engaging Facebook applications.

15. SCRABBLE Beta – 34.6%

-Scrabble Beta Icon-While the Agarwalla brothers still have the most engaging word game on Facebook, Electronic Arts has done a good job with their Hasbro licensed version of SCRABBLE. The application has almost 200,000 users returning to the application daily. It’s an impressive feat for any developer even if it’s one of the largest gaming companies in the world that developed it.

The application has been in “Beta” for months now so I’m not sure if the company ever plans on changing that. Scrabble is clearly a popular game and Facebook has proved to be a great platform for creating turn-based games like Scrabble. If “Wordscraper” wasn’t good enough for you, you can check out Scrabble Beta if you are in the U.S. or Canada.

16. Pet Society – 34.34%

-Pet Society Icon-Playfish is currently the second largest application developer on Facebook based on daily active users and their game Pet Society is the largest application based on daily active users. As I previously wrote, social games tend to be the most engaging applications on Facebook and Playfish is dominating this space with Zynga.

Pet Society is essentially a much more robust version of (fluff) Friends which let you create a pet and care for it. The application includes games for you to play with your pet inside of a large virtual world. As you travel around you can win gold that can be used to buy items to decorate your house. There is honestly more stuff to do in the game then I had time to check out but it’s not surprising that this game is the most visited game on Facebook.

The game continues to grow by leaps and bounds, currently attracting over 2.3 million daily active users. If you haven’t played Pet Society yet, I recommend checking it out.

17. MouseHunt – 34.32%

MouseHunt has been a huge success. Since the launch, the application has continue to surge in popularity. The developers of MouseHunt were also winners of the FB Fund. MouseHunt is a highly addictive strategy game in which you try to catch as many mice as possible, all of which have highly detailed designs. The game currently attracts over 107,000 daily active users and continues to grow week after week.

With cash in the bank and a continuously growing application, my guess is that the developers of MouseHunt have a bright future ahead of them.

18. SCRABBLE® Worldwide – 34.30%

-Scrabble Worldwide Icon-There isn’t much I need to say about this one. Scrabble Worldwide is a duplicate of the SCRABBLE Beta application except it’s licensed for users outside of the U.S. and Canada. Determining which version of Scrabble you’d like to play is pretty much based on your location and whether or not you want to play the “official” version or the version licensed by the Agarwalla brothers.

If you are outside the U.S. and Canada and prefer playing officially licensed games, check out Scrabble Worldwide.

19. My Fairyland – 33.5%

-My Fairyland Icon-Taking inspiration from the Grow-a-Gift application, My Fairyland is an application that lets you create your own garden to grow flowers and fairies. You can also help out your friends by watering their gardens as well. This application is nowhere near as robust as some of the applications we’ve looked at but around 68,000 people continue to return to this application daily ranking it in our list of the most engaging Facebook applications.

If you are into flowers and fairies, then I suggest checking out this application!

20. Facebook for iPhone – 33.2%

-Facebook for iPhone Icon-Last on our top 20 most engaging Facebook applications is Facebook for iPhone. This one has clearly been a hit. It’s also somewhat surprising to see that the Blackberry users use their mobile Facebook application more often then iPhone users. Despite the surprise, the Facebook for iPhone application is one of the most popular iPhone applications ever with over 5.2 million users and it continues to grow daily.

If you have an iPhone then there’s a good chance you’ve already downloaded this application. If not, you should definitely download it!

Conclusion

I decided to leave one application off of this list because it was clearly a spam application and I don’t foresee it having a long life-span. Aside from that, these are the top 20 most engaging Facebook applications. For this list I only selected those applications that have over 50,000 monthly active users. I probably could have made the limit even higher but I figured 50,000 was a good cut off.

There are clearly a number of lessons learned from taking a look at those applications which are the most engaging.

Virtual Gifts Are Huge
First, virtual gifts are a huge incentive for users on Facebook. The better the design, the greater the incentive for users to take action. If you are planning to make money on Facebook, make sure that virtual gifts are in your business plan. While there are many other factors that determine the success of a Facebook application, virtual gifts were a common thread among many of the most popular applications we saw.

Games Rule the Facebook Platform
Not surprisingly, social games rule the Facebook platform. If you are looking to launch an enterprise software application, Facebook is not the place to do it. Users on Facebook come to the site for entertainment. While I believe that Facebook Connect will provide a more social experience elsewhere on the web, possibly for more productive uses, currently all Facebook users want to do is to have fun!

Applications Haven’t Advanced Much Beyond the Early Days
Our previous search for the “golden application” on Facebook has turned up nothing. If anything, I’d currently have to give that award to Pet Society since the application is completely dominating the platform. There are many close runners up though but anything beyond entertainment has yet to make its way to the top applications.

Also, scratch off tickets have been popular since early on. I’m not sure if it’s surprising but almost two years later, we still have a somewhat similar image of the Facebook platform landscape.

Facebook Users Like to Gamble
The biggest lesson from exploring the most engaging Facebook applications is that Facebook users love to gamble. Perhaps the real lesson is not that “Facebook users” like to gamble but instead that gamblers like to gamble! Slots and scratch off cards appear to be the Facebook crack. There’s no doubt that the developers behind the gambling applications are bringing in some solid cash flow from the gambling addicts.

Here’s to the gambling and gaming addicts because if it weren’t for you, there probably wouldn’t be a booming Facebook platform.