Jared Atchison

This plugin is for bbPress 2.x
Many people who run forums would like to know when a new topic (thread) has been posted but do not have the time to constantly check their forum for activity. This solves that!
This plugin will send an e-mail notification to specific addresses when a new topic has been posted. The users who receive notification along with a simple e-mail template is configured in the bbPress settings.
See the <a href="http://www.jaredatchison.com/2011/08/28/bbpress-new-topic-notifications/" rel="nofollow ugc">author website</a>.

bbPress New Topic Notifications

Send notification emails to specific users when a new bbPress topic is posted.

Jennifer M. Dodd

bbPress Email Notifications provides users with various email notifications relating to forum changes, as well 
as the ability to turn these notifications off. It overrides the bbPress-provided ‘Subscribe’ function, 
allowing users to turn all subscribed topic notifications off and on in one location.
BuddyPress users can update their bbPress email preferences at Member > Settings > Notifications. WordPress 
users can update their preferences at Users > Your Profile.
This plugin deals solely with bbPress plugin forums, and not with BuddyPress group forums.
Filters are available for modification of plugin behavior.
<h3>Credits</h3>
Development funded, in part, by Ariel Meadow Stallings and the Offbeat Empire.

bbPress Email Notifications

Provide notification emails and controls for bbPress subscriptions, merge, and split functions.

bbPress New Topic Notifications vs bbPress Email Notifications