If you delete an Adgroup, can you ever use the same Adgroups name again?
Heheh. This is another one of those questions that I've never heard come up before, Jon12345. ;)
I just went to my own account and tried creating a new Ad Group with the same name as a deleted Ad Group, in the same campaign - and it told me that the name was already taken. So, in the same campaign, the answer is no.
On the other hand, I was able to create a new Ad Group with the same name as a deleted Ad Group, in a different campaign. So in a different campaign, the answer is yes. :)
As an aside, I also tested creating a new Ad Group with the same name but with the number 2 added, in the existing campaign, and it worked fine also. So this may serve as a useful work-around.
AWA