With great improvement of wordpress platform, there are glitches where spammers can easily get through and make post or edit contents. That's a nice tip there how to protect wordpress blogs.
Here are some tips to hackproof WordPress blog-
1. Always keep wordpress updated
2. Set up an unbreakable username and password
3. Use secondary account for posting
4. Lock down your sensitive folders
5. Pick your plugins and themes carefully
6. Backup your wordpress blog periodically
7. Install Security Plugins to scan for threats.