If you are feed up of all the spam comments you are getting on your wordpress blog then you can easily avoid so by using the plugin:
Stop Spam Comments

This plugin is Simple, lightweight and effective spam comment blocker for WordPress.

Some of its Features:

1. Simple: No setup required, just activate it and enjoy your spam-free website.
2. Lightweight: No additional database queries is required.
3. Invisible Design: No captchas, no tricky questions or any other user interaction required at all.