9ox.net now uses Google Safe Browsing API to reject phishing and malware sites. It's already using SURBL and WOT. I guess I don't do any changes before converting to Python 2.7. All changes this far which I have made, haven't affected database structure. Therefore it has been relatively safe to do these changes.
When I'll implement Python 2.7 and multithreading, that's right time to fix the database structure. I have one known performance bottlenecks which is caused by bit bad implementation, and it's directly related to bad database structure design.
Now it's good time to study something else for a while. I think I'll check out some compression and hashing & encryption algorithms.