Seattle gamification startup BigDoor has acquired OneTrueFan, a San Francisco company that has an internet check-in rewards system for businesses.

Terms of the deal were not disclosed. OneTrueFan, a small company with only five employees, says it is working on a new loyalty platform based upon BigDoor’s APIs and will launch the service soon.

Here is a BigDoor blog post about the deal:

Through this acquisition, we’ll gain access to an incredible team of web industry pioneers! OTF Co-founders Todd Sampson and Eric Marcoullier were responsible for IGN.com (IPO in 2000, acquired by NewsCorp in 2005), MyBlogLog (acquired by Yahoo in ’07) and Gnip. Not only do we now have access to this incredible team but also to thousands of publishers and technology that fit perfectly in to our gamified loyalty platform.

With the OneTrueFan acquisition, BigDoor said it is launching Bigdoor Rewards next month, which "will carry with it many of the same characteristics publishers loved from OneTrueFan: easy to implement, great analytics, and increased user engagement."

VentureBeat calls the deal “symbolic” because it is a sign that the gamification business, which helps sites draw traffic with game-like features, is maturing.

Founded in 2009 by Keith Smith and Jeff Malek, BigDoor has worked with clients such as MLB.com, DevHub and BuddyTV. For example, with MLB, BigDoor has added gamification elements to the site’s video viewing sections, so users can collect “badges” like baseball cards. Smith said this keeps users more involved and engaged with the site, and in turn, increases revenues.

BigDoor is backed by Foundry Group.