Allows visitors to quickly subscribe to your blog using only an email address
This plugin will add subscription buttons to allow users to subscribe to your RSS Feed and allows you to track your rss feed usage on Feedage.com
TweetScribe plugin connects your WordPress blog with TweetScribe.me
You can subscribe to an iCalendar or two iCalendars and display them on your page
Add an iCal feed to your site for the Events Manager plugin
Allow visitors to subscribe to your Direct Mail subscription groups.
With each new post an email is sent to every registered User in the Database. The email can be text or HTML.
Subscribe Here displays a visible plugin widget in the sidebar with Subscribe by Rss & Subscribe by Email(through Feedburner) options.