Hashtags and mentions

Two kinds of shortcut turn into links automatically when you post - just type them into your writing.

Hashtags

Write a #hashtag - like #music - and it becomes a link. Tapping it opens that tag's page, showing every post using it, so hashtags are a good way to group a topic and to discover posts about things you care about. Browse the active tags any time from Tags in the menu, and see which are catching on under Topics.

Only a post's first ten distinct hashtags are indexed onto tag pages and counted toward trending. Pile on more than that and the rest still show as links in your text, but won't turn up on a tag's page.

Mentions

Write an @username to mention someone. It links to their profile, and they get a notification that you mentioned them - handy for bringing a specific person into a conversation. Mention more than ten distinct people in a single post, though, and nobody is notified - the links still work. You can mention people elsewhere on the Fediverse too, using their full @user@server handle.