Mar 26, 2015 · 2 minutes

Twitter has released Periscope, the live-streaming iPhone app it acquired before Meerkat captured the attention of a million tech bloggers.

There's a lot to like about Periscope. It has a more attractive design than Meerkat, it allows users to communicate with each other via comments and "hearts," and videos remain available for later viewing instead of vanishing when the stream ends.

Periscope also has access to Twitter's social graph, which makes it easy to find the people you already follow on other networks. Meerkat had this ability, but Twitter cut off its access to the social graph after it became popular. Now, the advantage gained from making it easy to find the people you follow is Periscope's alone.

The rivalry between Meerkat and Periscope comes as live-streaming services -- and mobile video in general -- experience a sort of renaissance. Services like this were popular in the early days of the web, as Slate's Will Oremus notes, but fell out of favor when people realized that they're actually quite boring. (And filled with dicks.) That's changing.

YouNow has more than 100 million monthly visitors -- at least a few of whom like to watch teens sleep, which is exactly as creepy as it sounds -- and Twitch reaches a similar number with the game streams its users constantly upload. Then there's Ustream, YouTube's live-streaming feature, and other services.

Periscope and Meerkat are another example of something I talked about yesterday after Facebook introduced On This Day, a feature that resurfaces old content and makes it easier for people to see what they posted years ago: the ongoing struggle between ephemerality and permanence on social networks.

Periscope videos are uploaded to its service so they can be replayed by default. Users can stop this from happening, and stored videos can be deleted at any time, but the app assumes people want their videos to last after a stream ends. Meerkat doesn't do that; once something stops streaming, it's like it never existed.

The services both have their own appeal. With Periscope it's easier to actually watch a video instead of clicking on a link and seeing that a stream has ended, which is the only experience I've had with Meerkat thus far. But with Meerkat, people don't have to fear that their live-streams will be available in perpetuity.

The rivalry between Periscope and Meerkat hinges on the answers to a few questions: How important is the ability to easily find the people you follow on Twitter? Is it better to always have something to watch, or to know that your videos will disappear when you're done streaming? And will live-streaming last longer than it did in the past, or is it just getting another 15 minutes of fame?

Given that Twitter acquired Periscope instead of merely building it in-house, and Meerkat just raised a reported $12 million in Series B Funding, it's clear that some major players want to know the answers to those questions. I just wonder how many live-streams of office ceilings -- or dudes twirling their genitalia in front of the camera -- they'll watch before those answers arrive.

[photo by Jeff Kubina]