Dunno what this mod is called.....
 

...but I have seen it in action.

I tried a "search", but could not find it (maybe used wrong search terms).

Anyway, what I am looking for is the mod that requires a user to post in a thread before a specific link that is in the first post in the thread is shown to him. In other words, the link is invisible until he has contributed to the thread.

Sorry for the verbose description....anyone know where I can find this mod?

Thanks.

it's called hide hack or lockdown