Email Users is a plugin for wordpress which allows you to send an e-mail to your registered blog users, based on their role.
Enhanced Links allows you to list your links in a better way. Very useful when you have a great number of links and categories.
Livewords makes it easy to search the meaning of any word on your blog simply by selecting it.
Featuring Count Comments counts the comments of users who are registered.
unAPI Server gives full citation information for posts, including the abstract.