Whether in Blogger or Wordpress, make sure to employ comment moderation for all your posts, not just the recent ones.
You see, people are actually hiring other people to leave links on blog posts. Some may even be posting scripts that could basically 'steal' away your traffic. Don't let them ride on your blog's popularity... or at least, don't let their links fool your few visitors into getting who-knows-what when they click on a link. These comments become part of your blog's pages so make sure you have total control over every link there is on your site.