If we speak about German grammer, a final aphostrophe is almost not correct. Especially you don't show a genitive for a word that ends with a 's' with it. It is not english.

So, this sentence is correct: "Sagt mal, was ist eigentlich der Sinn hinter Clint Adams blog?!" (or as I would rather say "... Clint Adams seinem blog?!" :). And, so Clint is right.

Update: I was notified by two different people already that the current new german grammer disagrees with me. http://www.ids-mannheim.de/reform/regelwerk.pdf tells in ยง96 that the usage of the apostrophe is right. Well, of course I'm conservative and haven't upgraded to the new grammer. :) Besides of that, my feeling is still that the apostrophe is wrong.

Another nit-pick: The "... Clint Adams seinem blog"-style is known to be not official german. But it works quite well, and is even conformant to the new rules.