Why is PM not another Slash site?

Short answer:
Slash is simply a news/message board. Everything does Everything!

Long answer:

Quoting What is Slash?

"Slash is a database-driven news and message board, using Perl, Apache and MySQL. It uses persistence through mod_perl for a good speed and efficiency. Slash has all the features and more that you'd ever want in a bulletin-board/message-board system. You can customize it to anything you want, give it any appearance that you want. This can mostly be done via data in the database. Slash is a database beast in the true sense."

Quoting What is Everything?

"Everything is an information management system, using a combination MySQL and Perl to create a flexible system of entering, linking, and retrieving information. ... Any time you have information that would be enhanced through easy linking, facile access over a web browser, or would like to build shared meaning for an online community, you should consider the Everything System."