thread link to thread name in post

[soniceffect]

Seen this somewhere and done it before myself and its really annoyin me because I cant remember how I did it.

I know that somehow you can make it so that when someone posts a link to a thread (the actuall address) and posts the post/thread it changes the link to the name of that thread (hope that makes sense).

Please could someone let me know how I did it LOL.

[Dismounted]

I believe that feature is usually included in SEO modifications.