Bring back tags.
Following the successful feedback received from posters, this functionality has now been extended to all registered members.
To add a threadmark to a thread, click on the Threadmark button at the bottom of the post, beside where you would see the Edit button. If you’re on a mobile device you’ll need to access the post menu which is marked by 3 horizontal lines. Then you just give that part of the thread a name and you’re done. Simples.