Can anyone review my code?

I have over 20 years of experience developing desktop applications. Several months ago I decided to look into Web development finally. I looked at several CMS's and concluded that Drupal suits best my needs. After some configuring, installing modules, hacking modules etc. I decided to write my own module. Briefly, it is a module to link questions and answers.

As I've learned PHP and Drupal API while doing things, I suspect there is still stuff to learn. Therefore, I'd appreciate if someone experienced in Drupal development would do me a favor and review my module. The .module file is 20K with 555 lines of code. The .install file basicaly creates one database table.

I already ran my code through the code review module and fixed the reported issues. I even used the "picky mode" and fixed most of the minor issues. So coding style issues should be addressed. It's time to have a closer look at the logic, security etc.

Thanks in advance.