netmeg - 1:54 pm on Jul 9, 2013 (gmt 0)
Link units work differently. You click on one, and then you get a page full of ads (with thumbnails) almost like a search result. Or at least, that's what happened when I last used them. You can click on on a link unit without penalizing your account (but you can't do the "second click" on an actual ad) I think what HP is saying is that the second page with all the ads wasn't coming up.
The reason I stopped using ad links is because 1) they earn a lot less than they used to but mostly 2) they changed the way they render on anything other than a white background, and that doesn't work for the sites where I used them. I went round and round with support over this, till they finally admitted that it was a problem but that it wasn't a priority for them to fix it. At that point I figured the writing was on the wall for link units.