This is actually a reply to a comment I made that his blog was spammed.
So what is a SPAM?
As you can see from above, a spam is anything that looks like a advertisement, or a link that is unrelated to your blog. The funny thing in my example is the silly blogger actually replied to a spam, thinking it's a real compliment.
Anyhow, to answer the question, if you use the comments supplied by Blogger.com you can do something to reduce spams. Just follow the instruction below:
So what you do is this:
I'm using Haloscan instead and so far I have yet to receive any spam. So maybe if you have loads of spams, you might wanna consider disabling the Blogger.com comments and use Haloscan instead.
Hope this helps.