Ownership has been the key word at Facebook game developer Zynga this week.

The company launched its own social game platform, Zynga.com, in beta, while taking steps to acquire the San Francisco building where it is headquartered.

Bloomberg reported that Zynga will buy the building in the South of Market district for $228 million, having already deposited $25 million in escrow.

The building totals some 670,000 square feet, and Zynga had already been leasing about 65 percent of it.

As for Zynga.com, which was initially announced last week, Facebook users can log into the site via Facebook Connect and access their games at the exact points they were left at on the social network.

Any actions players take while playing on Zynga.com will be reflected the next time they access the games via Facebook, and vice versa — just like what happens when you toggle between Facebook and the mobile version of a Zynga game.

Game players will likely see speedier game play by accessing their games via Zynga.com, although sister blog Inside Social Games reported that access speed was about the same as via the social network, and the developer said it would add offerings from other developers in the future.

Zynga.com launched with five of the developer’s top games:

  • CastleVille;
  • CityVille;
  • Words with Friends;
  • Hidden Chronicles; and
  • Zynga Poker.

The past few months have been a roller-coaster ride for Zynga, which launched its initial public offering in mid-December, at $10 per share, but reported a $978.6 million net loss for 2011 last month.