it is literally the same "tags" we already have with XenForo 1.5
Just giving the user the ability to add some "tags" to his Profile-Page.
Thereby it is easy and quick to find other users with common interests and therefore fuel discussion.
Also, you can find threads based on your interests immediately after filling-in your Profile-Page with these "interests".
It is not a big deal to implement this.
It is just the ability to put the already existing "tags"-system onto the "User Profile".
My mockup above is not great from a "design perspective".
It needs to be made a bit "nicer".