They're especially prevalent during televised events--the Super Bowl, the Golden Globes and the Olympics all had second screen apps. It makes sense, they're the type of performances we usually watch in real time, and with so much pop culture influence, people want a platform to discuss what they're watching. It's perhaps a poor substitute for a group of friends at a super bowl party, but analyzing your team's defensive plays with other fans online is still more satisfying than yelling at the TV alone.
Scripted shows are also taking advantage of viewers' second screen tendencies. Companion apps offer character backgrounds, episode analysis and even show-themed games. Water-cooler talk is so yesterday. Now you can float conspiracy theories with other "Homeland" devotées while you're watching, not the next day. The Showtime Sync app will even identify the show and episode you're watching by sound and automatically take you through its companion program as the episode progresses.
And while it may strike you as simply an exploitive measure to monopolize more of your time and attention, for some fans, sharing their favorite show makes it much more enjoyable. It's a step toward making TV a shared experience, but in a totally new way. It's interesting that, even as we move away from traditional live TV viewing and depend on DVRs and internet streaming to catch up on our shows, technology has also found a way to make it more fun to watch live TV again and share the experience virtually.
Tell me, do you use a second screen?