Lemmy and kbin are #reddit alternatives with different communities similar to subreddits. If you already have a #mastodon or similar #fediverse account, you don't have to necessarily register for a new lemmy/kbin account to participate. Search for a lemmy community you want to follow: https://lemmy.ml/communities/listing/_type/All/page/1 Go to the community, then copy and paste the URL into your mastodon/fediverse search to follow it locally. Mention the community in a post to submit to it, like: @edtech #EdTech