When it comes to blog spam there are several ways you can control the spam to keep it to a minimum. Some of them are very effective in controlling spam and others are less so. The most effective spam control measures are a combination of methods, which are described below:

• Use a Spam Blocker – If your blog is on Blogspot or WordPress.com then you’ll have a built-in spam control measure, but I consider Blogspot’s too restrictive. In essence, if you expect a lot of comments from other Blogspot users then it’s effective; otherwise, you’ll discourage useful comments. WordPress (standalone version) uses Akismet, which is very effective in caching most spam and doesn’t restrict good blog comments. You can manage all your own comments and approve the ones that you think are good and ditch the bad ones.
• Manual Comment Management – I highly recommend that you monitor all of your comments. This allows you to approve the ones you like and the ones you don’t. If you use this method alone, however, you’ll spend all of your time managing comments. That’s why I recommend this method in combination with using a spam blocker. The spam blocker won’t catch everything, but the comments it won’t catch can be caught manually and your blog readers will not see comments until you approve them.
• Require User Registration – Perhaps the most effective spam control method is to require all commentators register and be signed in to leave a comment. This is what Blogspot does and I don’t like it. You will lose some commentators this way. People who will leave some of the best comments on your blog will leave without commenting if you make it too difficult for them. WordPress allows you to choose this option, but I don’t recommend it. If you use the Akismet spam blocker plugin and monitor all of your comments then you will catch all of the spam before any of your visitors see it.