Entertainment check-in apps are vying to supplant photo-sharing and Q&A services as the new new thing in social media. Yahoo gets a much-needed social – and mobile – jolt by snapping up IntoNow, which makes entertainment check-ins easier by recognizing TV shows via audio pattern matching (much like Shazam recognizes songs). It just cleverly applied the trick to Pepsi ads. IntoNow is competing with Miso, GetGlue and others to create social entertainment experiences that get viral distribution via Twitter and Facebook feeds. They all feel scarily like features rather than products, but there’s no question that the category is vibrant and inspiring lots of innovation. To what end, though?