Kwaga, the company behind Gmail-integrated address book updater WriteThat.name, has just acquired Boxcar.io, which set the bar for organizing push notifications on iPhone pre-iOS 5. While Boxcar hasn't been updated in almost a year, the company got into the push notifications game early, letting users customize notifications from a variety of services like Twitter, Facebook, and email. The company's site claimed that it was currently working on an app for Windows and Android to go alongside its Mac and iOS app.

According to Kwaga CEO Philippe Laval, an obsession with "attention management" brought the companies together. Boxcar founder Jonathan George will join Kwaga's board as an advisor and work on "join development projects" that bring Boxcar's notification expertise to WriteThat.name. It isn't immediately obvious how Boxcar will help Kwaga, but you could speculate that a new version of WriteThat.name could incorporate push notifications on mobile devices to alert users when contact info has been changed in a user's address book. Laval told The Verge that Boxcar will continue to operate and receive updates normally.

Kwaga and Boxcar.io refused to comment on the purchase price.