Periscope as a self-contained service won't be disappearing anytime soon, however. "Our apps and web player on periscope.tv remain the best place to search and discover Periscope content," the team said in a blog post. While that may be true, the reasons for downloading and using the Periscope app are now greatly reduced. All but the most diehard Periscope fans will be better served by the Twitter app, streaming from the compose interface and watching the broadcasts that pop up in their feed.

For Twitter, it's an opportunity to reinforce video and livestreaming as a fundamental part of its service. The company has inked a few broadcasting deals, spanning the NFL, Wimbledon tennis and the US Presidential debates, but much of its value comes from user-submitted contributions. That's what makes it such a valuable tool for activism, citizen journalism and general public debate. The rise of Facebook Live threatens to erode that utility, while publishers, celebrities and brands hunt for larger audiences. Twitter and Periscope's fusion was inevitable -- the question is how long the company keeps the latter around as a standalone entity.

We all saw what happened to Vine.