Has Facebook peaked? The answer in the US is yes and about two years ago
Bottom Line: Facebook is the undisputed king of social media. Whether world-wide or in the United States there isn't another a pure-play social platform that has even half of the usage (and the closest is Instagram which is also a Facebook company). During Zuckerberg's testimony he indicated that there haven't been widespread defections from Facebook despite all of the talk about users deleting accounts. That may prove to be the case, but something was already evident. Facebook as a service appears to have peaked in the US in 2016. Here's the latest usage based on data from Pew Research:
68% of all adults have a Facebook account (that's unchanged from 2016 & 2017)
74% of women have accounts compared to 62% of men
74% of users access it daily (unchanged since April of 2016)
45% use it for news and information
Only 5% say they have a lot of trust in Facebook as a source for news and information (33% said some)
Put it altogether and here's what you get. Facebook hasn't grown in two years in the United States and the only categories where there's been a change, it's been negative. During the 2016 cycle more than half used it as a source for news and information and while we don't have comparable information on the trust level of that news (that came after the controversies regarding Facebook's potential bias/issues arose), it's probably safe to say that it has declined as well. I'm not sure where all of this goes from here, but technology is ruthless and the past twenty years alone have demonstrated how the titans of yesterday are commonly yesterday's news.
Once upon a time AOL was the name in internet. Netscape was the browser. Yahoo was the search engine (and AskJeeves before them) and Dude you were getting a Dell (or a Compaq as the case may be). There's a chance Facebook comes out of this cycle on top for years to come but history suggests there's at least an equal chance it doesn't.