Make a link for a thread or follow a link.

To link a thread, is similar to tagging a user. Just type the @ symbol and then start typing the name of the link. 
eg Best Friends Club then choose the thread from the drop down box.

To follow a link just click on the blue writing. 

note: you can click on blue usernames too and that will take you to that user’s profile where you can see where they have been posting.