You don't need us to tell you that Ted was a massive hit last year, and when films make over ten times their budget at the box office, sequels almost become an inevitability. It's been known for some time that Ted 2 was going to happen. What has held things up however was Seth MacFarlane's work on his second big screen directorial effort, the comedy western A Million Ways to Die in the West. That movie is set for release in May 2014 and will star MacFarlane, Liam Neeson, Amanda Seyfried, Charlize Theron and Giovanni Ribisi.
With regards to Ted 2 though, the wheels are very much turning. MacFarlane has now revealed that the target release date for the movie is Passover 2015, which would make it April 3rd 2015. This date would give it a month before The Avengers: Age of Ultron is released. But with the small matter of the release dates for valet/Superman, Star Wars Episode VII and Jurassic Park 4 yet to be confirmed, there's a fair chance that Ted 2 could face some stiff competition (although it does, so far, seem to have the comedy demographic to itself).
MacFarlane and Mark Wahlberg have been keen on a sequel to Ted for some time so their decision to go ahead presumably is more down to their desire to play the characters again rather than it being purely financially motivated.
More news on Ted 2 when it's available.