This plugin automatically crossposts a blog entry to your LiveJournal (or LiveJournal-based clone) account.
The Akismet plugin for b2evolution checks feedback through a central service ( http://akismet.com ) against spaminess.
This widget displays the latest posts sorted by main category.
This plugin allows you to send emails to registered users. You can exclude users and groups, specify message encoding, send as text or/and HTML, attach files and receive detailed reports on selected email. Advanced users can use external emails source.
This plugin allows you to password protect your posts, and visitors would have to enter right password to view post content. All passwords are stored in cookies (if enabled in plugin settings) and visitors don't have to enter them every time. Please note: - it doesn't hide post comments. - it's still under testing, and there might be some bugs.