Webcrossing Subscriptions

Webcrossing Community allows registered users to "subscribe" to various folders and discussions. What this means is that the software will track which messages they've read and show them only the new messages.  What happens after that depends on the type of subscription the user signs up for.

You can allow users to do any (or none!) of the following:

• Subscribe by web - users either go to the Message Center for a list of their new messages, or click Check Subscriptions in the toolbar on any page. Each time Check Subscriptions is clicked, the users will be taken directly to the next new message on their list without having to return to the Message Center in between.
  
  This is really an amazing "power tool" that many sites don't understand and subsequently turn off.  It allows somebody to instantly view all the new material on the site (in the areas they're interested in) without clicking around or being inundated by email notifications.
• Subscribe to email for individual posts - users receive whole posts in email
• Subscribe to email notification for individual posts - users receive links back to the forum and notification that a post has been made, but must visit the forum to read the new messages. Users will not receive further notification until they have visited the forum and read the unread messages. This prevents spamming people with notification messages before they are ready to visit.
• Subscribe to email digests - users receive an email digest of all new posts, arranged by discussion, emailed at the time of their choice. The interesting thing about this is that digests don't come at some time determined by the site owner or whenever there is enough material, but instead at the time the user chooses. You an get 24 digests a day if you want - one an hour. Or just one a day. Or just one a week.

Users can subscribe to everything, nothing, or any combination of subscription methods - to the entire site, or to just a subset of areas that interest them.  You could subscribe by "check messages" to the Dogs folder and by email digest to the Cats folder.  The only limitation is that full notifications vs. individual post notifications is a sitewide setting for the user.

Subscriptions are definitely a "power feature" of Webcrossing Community.  Webcrossing Neighbors has some additional subscription features by virtue of its social networking emphasis.