Yeah Facebook is able to leverage peer pressure in a big way, yahoo had email but with facebook messenger if you cancel out you lose access to communication with a lot of people. Not even google was able to make a dent in facebook, google plus turned into a broken joke.

AOL/AIM used to be Huge. Now not so much.

It didn't help that when the buzz and hype was greatest for Google Plus they... didn't let people join Google Plus without a difficult-to-obtain invite. By the time they cut that out nobody gave a shit anymore.

Turns out Cartman's "you can't come" technique doesn't work so well IRL.

It worked for GMail though.

Yeah, it did get some buzz going iirc. Gmail doesn't rely on network effects tho.

what would kill facebook is p2p util to store digitals (photos, links, status, etc) and share it with others.

If only that would happen. It just seems corporations even outside of Facebook feel they have to lock people down as much as possible. It's annoying as hell. Like I've noticed there's very few apps on Android or iOS where you can just type in an Internet stream URL like you can with Screamer Radio on Windows (I don't know if there's a Mac equivalent). And one of those apps, TuneIn Radio, is becoming more locked down. Like I've had a hell of a time adding DRIVE Radio to it a week ago. This is just for internet radio of all things. What possible reason could there be to lock down such a thing? What real profit can they squeeze out of approved internet radio stations? Sorry for the digression into this pet peeve of mine but it seems it's all tied to the whole Facebook being the Internet concept. It's like they can't deal with just being a service or an app anymore. Gotta control the whole process from inputs to outputs and/or consumption. Can't have it your way. "No sir, that's not an approved fork for your meal, you must use our Brand X Ultra DeLuxe fork.." Bleh!

Something like Twitter, then?

Facebook will probably get the antitrust treatment, just like other pre-internet infrastructure like oil and telephone did