As we saw during the presidential election, Twitter makes watching TV a lot more social. Sidecastr, a new start-up, has built a campaign a new app that aims to be a companion tool for watching TV in real time.

The free app pulls all tweets related to a particular television show into one stream so that users can watch an episode unfold with other fans. Users can check-in to a show that they are watching to participate in the live stream of tweets.

The app is clever to avoid spoilers. It tunes into the user’s audio just in case the playback is slightly slower in one broadcasting zone.

Users can also customize content to remove topics they don’t care about and to prioritize other topics. For example, a user watching Mad Men could avoid all tweets involving “set design.”

At this point the app works for specific TV shows including: Anger Management, Breaking Bad, Dallas, Big Bang Theory, Glee, Mad Men, Modern Family, Real Housewives of New York City and Saturday Night Live, among others, as well as various sporting events. Users can follow these shows live during a broadcast and the DVR-inclined can watch archived versions of the Twitter stream.

The app is ad-supported. Sidecaster founder Steve Brand told The Boston Globe that advertisers who sponsor the television shows could benefit from the tool. “They can use real estate on the app, and real-time interactivity to engage with these rabid fans,” he said. “Companies that have paid for product placements might also want to highlight those when they appear on the show.”