I jumped on the Mastodon train last April when the population started to grow more quickly. I've always been more of a forum/message board user than a microblogger, though, and was hoping this space would take off in a similar way (if not for similar reasons, or for them, as the case may be).
I'm very bullish on decentralization for the forum/aggregator space, since that's fundamentally where these types of communities have their roots anyway, so I'm excited to see people showing up.
Hopefully we're nearing a population size where significant quirks can get ironed out, but with an audience that is technical or avant-garde enough to put up with them for a bit.