So Long Meerkat, Hello Periscope
Just a few weeks after livestreaming app Meerkat took over the Internet (and was subsequently squashed by Twitter for being a parasitic app), Twitter launched Periscope, a livestreaming app of its own that it acquired back in February.
Periscope will enable users to stream footage directly from their devices to their followers; viewers can comment and send "hearts" to the streamer and footage can be replayed later — a key difference to Meerkat, where the footage is gone for good once the stream is over.
Periscope videos aren't integrated directly into Twitter, however, so its neccessary to install the separate app (which is limited to iOS at the moment).
Twitter also owns Vine, the short form (6-second) video app, wherein clips can be embedded directly into users' Twitter timelines and viewed without leaving the main Twitter app.