Having tried some traditional Sonic the Hedgehog gameplay with Sonic Episode 4 (which didn't seem to do that well for them), Sega has now moved to the strategy of using Sonic in much simpler, arcade-style iOS games. Sonic Jump came out a little while ago, featuring an endless jumping/Doodle Jump-esque premise, and now Sega has announced Sonic Dash, an endless running game featuring all of the series' mainstays.
It's a 3D game, however, so it'll likely have a lot of similarities to Temple Run, which is certainly a franchise that a lot of game developers have been emulating lately. Sonic Dash is due out "soon" on the App Store, which probably means later on this week. We'll keep an eye out for it then.