Spam & form mail

I hope I'm posting in the right topic..I am getting tired of deleting spam from Blogspot.com.
I help a friend of mine run his website, and every day, we get 20 or so forms that have nothing to do with our business...They put in a fictitious name, and in the comment field, they will put something like "great forum" and a bunch of links to viagra, or rape porn or realestate.

Is this doo-doo coming from blogspot, or is someone getting paid to do this?
All I know is, that when I get 50 or so e-mails just from blogspot, and maybe a hundred or so legit e-mails...it becomes a lot of work, and waisted time just deleting unwanted spam.
I have never been to blogspot, or any other blogging site, as I have no interest in blogging.
Can anything be done? And can we hold Websites responsible for our waisted time and bandwidth?
Companies need to be held accountable for advertisers who spam people in the name of their business..In other words, I should be able to sue Blogspot.com for harassment, Right? I mean if someone calls you on the phone constantly and you tell them to stop, you can sue them if they don't stop.
Same thing should apply here.
And so ends another rant from the Doc

why not just have a spam filter in whatever program he is using to get his email that deletes anything from blogspot?

You need to change the code behind your forms, it's the only effective way I know of to stop this kind of spam. The best method appears to be using a hidden field the bot will see but real users do not, if the hidden field is filled-in then reject the mail send. It achieves the same thing as typical CAPTCHA's without any user action so it's preferred.

First of all thanks for the replies, and El Maxi, could pm me and give me an overview of what that would take? It would sure help out my job a bit.
I am going to set the spam filter for blogspot, but that is only half the problem.

I personaly never had any problem with spam, because almost nobody has my e-mail address, so dealing with spam is kinda new to me.
Thanks again,
Doc