vBSEO url hack?

I've noticed on some forums that when a URL is posted, it shows up in the post with the meta name (I think?) instead of the actual URL spelled out.

Is this a hack of some kind? If so, what is it?

It's a feature of vBSEO.

Check out the vBSEO Control Panel for "Add Thread Titles" and "Add Titles to External Links" options.