WordPress MU

I have spammers problem and mostly they start creating users and a lot of blogs I like to learn is there a way to know a blog has not touched after its created. with this way at least I can clear empty blogs.

thanks in advance

yepp, I think there is a last modified date or so, but you could use a tool to prevent them signing up, i.e. montyspam, typepad solution or akismet, then to delete untouched blogs, use the power tools plugin.

I am trying to clear blogs not stopping spammers. because normal users does that too. anyway is there any tool or piece of code does this action.

thanks in advence