WordPress as a framework? 5 ways businesses can replace web apps with WordPress

WordPress has been doing a decent job of shedding its reputation as being "just for blogging" and gaining more respect as a full-fledged content management system (CMS). 

Some dedicated developers in the WP community are going further, building plugins that allow WordPress to offer the same functionality as popular web apps:

5 innovative uses of WordPress for business owners

One attraction would be greater integration with your website.  Instead of juggling your WordPress site and a bunch of third-party apps, you could control them all from the WP dashboard. 

I'd say these plugins are in their infancy, so people shouldn't expect the full features of more well-known programs.  For example, CollabPress is far from being the next Basecamp.

In particular, I'd be wary of using WordPress for e-mail marketing.  "Deliverability" is a full-time job in itself, best outsourced to professionals.  E-mail providers are constantly updating their spam filters, and trying to get past them is a time-intensive endeavor.  I'd still go with MailChimp or Aweber for managing e-mail newsletters.

Have you found any cool plugins that transform WordPress into a different kind of website?  One thing I'm looking for is a theme or plugin that creates a Q&A website like Quora or Stack Overflow.

Share your favorites in the comments.