Mark Zuckerberg revealed Meta is testing a new tagging feature for Threads that’s like hashtags, but not exactly. Yes, you’ll use a hashtag to create or add to a topic’s conversation, but instead of showing up as a hashtagged word, Threads converts it to a blue-text hyperlink. Australian users will get the first crack at it in the initial “limited test” before it gets a wider release.
Typing a “#” into the post text field brings up a card with the topic you’re tagging or other, similar ones. Underneath that, each of the topics comes with a count of posts about it, just like Instagram does.
Those with Threads’ new tagging feature can only add a single topic to a post at a time, which will probably limit anyone hoping to spam their posts for better reach. But again, this could be a nice thing, especially if you like the clean look Threads has (for now), or for anyone who hates in-line hashtags. Meta says it will continue to work on the feature as time goes on, so this first version probably won’t be its final form.
https://www.theverge.com/2023/11/15/23963101/meta-threads-instagram-hashtags-trending-topics