Here are my details about my Roundcube deployment. It's working quite well so far and am excited about the new plugin API, I originally installed Roundcube from the Ubuntu repository, but upgraded to 0.3 because of the plugins.
Number of users (max): 50 Average of concurrent users: 10 Number of hosts serving Roundcube: 1 Database backend software: MySQL IMAP backend software: Courier, with an Other webmail software which is offered as alternative: None
Some of the active plugins: Keyboard Shortcuts Help Automatically Collect Adddress Archive _______________________________________________ List info: http://lists.roundcube.net/dev/