this extension enables you to send your articles to users of your website via e-mail automatically. when you create or save an article, e-mails will send automatically to users.
also you can determine some filters to control sending e-mails:
-filter for articles
-filter for categories
-filter for usergroup
-filter for users
UPDATE:some users informed me that there are some problems in extension working. I fixed these problems. please download it again.
If you have problems with this plugins, at first please check it's settings.then check your e-mail settings option and try with other options.
Some of the problems are related to conflict with other plugins. If you change the order of the plugins on backend , these problems can be solved.