What is Tildes?
Tildes [tildes.net] is a social media website with upvotes, downvotes, threaded comments, and tags where users can post links and topics to be discussed as threads. In other words, it's a link aggregator.
Currently, it seems it's not possible to post images or videos directly on Tildes, making it a mainly text-only social media. It's also invite-only for now.
Threads must be posted to groups presented by a tilde (~), e.g. ~games is the a group about games. Each post can also have tags that can be clicked on to find all posts on that group with the same tag.