Pornographic spam comments on my blog

On my blog, I am getting loads of comments that are pornographic in nature. I have deleted them, and banned the IP adressess they come from.

I could turn on the feature that I have to approve all comments, but people do like to see their coments straight away don't they, or I can change my settings so only registered users can comment, but I didn't really want to do that, as I want legitimate people to be able to interact and comment easily. Everyone get SO fed up with having to log in all the time, I know I do!

Has anyone else had this problem? What do you suggest?

Thank you

If party in on without invitation, then you have no control on the crowd, unfortunately making visitors to register is one step towards reducing the spam, mind it, even this is not full proof, but count will reduce, if you want almost zero level of spamming then you need to enable e-mail validation on registration. I know its not a good idea and the genuine user get annoyed, but that's how it is for now.  I have no e-mail validation, and i get about 5-10 spam per day in my forum, earlier when it was open to all i use to get 50 to 60 every day.

I have made it so users have to register,  and that seems to have stopped the spam.   Not a major issue at the moment,  so I will see how that goes