Well don't be disappointed. They try and will keep on trying. As mentioned above, they are spammers. And they don't care...they have no ethics. Nothing to worry. After all what you can really do to them...Nothing except holding your heads and deleting the links. Now why do they keep on trying. That is beacuse sometimes...and i mean only very few times, they may get through. Really Need an example i just saw. Check out the famous directory LinksArena. Latest Link: http://www.linksarena.com/detail/link-4982.html This looks nothing more than spam I'm more than sure that this ain't paid. So that's what happens...sometimes.
@Formula: I see your directory as PR 6 so no worries BTW, i got this problem just a few times as i dont get much submissions cos of the niche i've chosen for my directory
I get it even to my niche art directory which is strange... why should I include viagr$ website over there???