In its infancy, Facebook login was restricted to those with a Harvard email address. Later, membership was extended to other Ivy League schools, and eventually colleges and high schools around the world. It wasn’t until 2006 that Facebook login was available to anyone over the age of 13 — a limitation that also may change in the near future.

Today, Facebook login has extended beyond the walls of even Facebook itself. Other sites and applications are integrating Facebook information into their sites, as well as allowing users to sign in to their sites using just their Facebook login information.

Here’s an ultimate guide to Facebook login to showcase the past, present, and future of Facebook login.

Facebook Login Over Time

To refresh your memory, or for those of you newer to Facebook, take a look at how Facebook login has changed over the years.

As you can see, Facebook hasn’t changed much over the years — on the surface, at least. Users simply log in by typing their email address and password, or signing up if they don’t already have an account.

It wasn’t until Facebook unveiled the social graph that logging in to Facebook became tricky — at least in terms of understanding where your information is going. Now, it’s what goes on behind-the-scenes when you connect to Facebook that mystifies most users.

Your Facebook Info On Other Sites

When you are logged into Facebook, you may notice some personalized Facebook info popping up on other sites.

Using Facebook’s social integration tools, like plugins and instant personalization, sites can now display content that is custom-tailored to you and your interests, and feature things that your friends have liked or talked about.

The Facepile

The Facepile is a social plugin, also known as a “widget,” used by sites to display users who have liked, shared, or otherwise used their site. When you are logged in to Facebook, the Facepile will be customized to show your friends.

With plugins, sites are able to display information from Facebook, while maintaining your privacy. This plugin is simply code that shows information sent directly from Facebook — the site or app itself does not actually have access to your data. The info will only be displayed when you are already logged into Facebook.

Instant Personalization

When you log in to a site that leverages the Facebook open graph, you’ll be able to get personalized content based on information from your activity on Facebook and your Facebook friends. For example, on TripAdvisor, you can see reviews and recent activity from your Facebook friends.

Unlike sites using plugins and widgets, these partner sites do have access to your basic and public information. You can disable instant personalization on individual sites — usually in the upper right.

Or, you can disable instant personalization entirely:

  • Go to your Facebook privacy settings.

  • Select edit settings next to apps and websites.

  • Select edit settings next to instant personalization.

  • Uncheck the box at the bottom.

Using Facebook To Log In To Other Sites

Many websites now allow users to quickly and easily connect and register, simply by logging in using their Facebook accounts. This convenience, however, does come with a few consequences.

At minimum, connecting to a site or app via Facebook requires permission for the app to access your basic information. Basic information includes your name, profile picture, gender, any networks you belong to, your user ID, your friends list, and any other information you’ve made public.

As users transition to Facebook timeline, the new Facebook profile, many of their past posts may become more prominently displayed on their profile. And some past posts may be publicly visible.

In addition to basic information, apps and sites may ask you for extended permissions to do anything from posting your app activity to gaining access to your friends’ information.

Below is a breakdown of the permissions boxes you might encounter when logging into a site using Facebook.

Restricting App And Website Permissions

Because your information can potentially be accessed not only by apps that you connect to, but also by apps that your friends connect to, it’s important to learn about Facebook privacy settings.

Here’s a step-by-step guide to restricting app and site permissions.

  • Select edit settings next to apps and websites.

  • Follow the steps in the image below.

Kristen Kato is director of content management at Grovo.com, an online training and education platform with video tutorials to learn Facebook and other social media platforms.