If you mean something that can make a splash in the social media space to address the "user agents on Facebook" problem, color me skeptical about the prospect of competing on useful features with the Facebook behemoth while fighting the complexity up and down the stack of making everything decentralized and trying to make it friction-free for casual users to run, with no funding from ads, and starting out at square one on network effects. Yes, Mastodon is a possible counter to this line of argument, but Twitter is so stagnant and their product is so simple that I feel like it's almost a unique case. And for most people the Facebook use case includes being able to find all their real-life contacts; by that measure even Mastodon would fail.