Do you want to increase your site usage and encourage users to post?
Posting by emails and getting updates by emails are the two most important things IMO for a small community sites. It is certainly the prefered way.
Configuration required on webhost or mail host for.
1. Setting up an email address or mailbox.
It is a bit time consuming to set it up, but its worth it. Check out the details at
http://drupal.org/node/39172 ( For BLOG Posts by email)
After successful implementation of above, a good user documentation is need to let the users know how to post in various forums on the site.