How does Google deal with Splogs (Spam blogs)

For people worried about the splogs and comment spams with Google blogger service, Google has been taking actions to prevent them, and has come up with these tools:

• Google has taken against spam blogs and providers bloggers with these tools: Google’s Blogger has implemented captcha (a type of challenge-response test used to determine whether or not the user is human) on new blog creation to avoid spammers who would try to automatically create thousands of blogs for nefarious reasons.

• Google’s Blogger has introduced a frequently-asked for feature, comment moderation. By using this feature, you can approve or reject what would-be commenters are looking to post before it goes live on your blog. It will prevent unwanted comment spam.

• Google provides "Flag" button. A person visiting a blog can click the "Flag?" button in the Blogger Navbar (the navigation that appears on the top of the BlogSpot blog), if they believe the content of the blog may be potentially offensive or illegal. Google tracks the number of times a blog has been flagged as objectionable and use this information to determine what action is needed.

And finally, here is a list of deleted subdomains deleted by blogger.