check out the fediverse

Lemmy is a link aggregator/reddit alternative

Mastodon is for microblogging (like twitter)

to enter the fediverse, you have to sign up for an account on an instance. there are a berjillion different instances to choose from and it can be overwhelming. this linktree lists some instances that are taking new signups - no matter which instance you choose, you can interact with all the rest of the platform (and other parts of the fediverse).