With this release we've done a few things with subscriptions
1. Exposed personalization settings so you can control how and when you receive the email subscription notifications. See the image below
2. The ability to selectively subscribe to email notification for content by Tag. At the top of the "Browse by Tag" page there is a new link to Subscribe with Email.
3. Made RSS feeds available for content based on Tag and based on Group. At the top of the "Browse by Tag" and "Browse by Group" pages you will see the RSS link.
4. The ability to subscribe/unsubscribe to individual posts. This is done with the Subscribe/Unsubscribe link that appears on the post listing as well as the post detail page for both Questions and Articles.
What is not yet improved and is in the queue to be done is the emails themselves, which are basic and lack any fancy formatting
To see your personalization settings go to the Subscriptions tab under My Account. Expand Settings and Preferences to see all of your options
Subscription by Tag can be controlled here: