It IS a Twitter-like site. It displays posts in more of a Twitter style. That being said - it is also part of the Fediverse, so theoretically you should be able to see all federated communities on any fediverse instance of your choosing.

Personally, I have a kbin.social account and a mastodon.social account. I’m doing this because Mastodon doesn’t really present threads from kbin or lemmy in an easily digestable way, so I will use kbin as my reddit replacement, and Mastodon to replace Twitter.