hello guys. i'm new to this whole Mastodon thing. is this some kind of a Reddit/Twitter alternative? is it dead? or what?

Liberdon

Liberdon is a Mastodon instance for libertarians, ancaps, anarchists, voluntaryists, agorists, etc to sound off without fear of reprisal from jack or zuck. It was created in the wake of the Great Twitter Cullings of 2018, when a number of prominent libertarian accounts were suspended or banned.