Subscriptions let you get email updates whenever new content appears in an area of the community that you're interested in. You can subscribe to a board, a blog article, an idea exchange, or any other location in the community. You can also subscribe to a specific post.
Look for the Subscribe button in the toolbars. Click it and you'll receive email when new content is posted in that area.

To view and manage your subscriptions:
Choose My Subscriptions from the profile menu found by clicking your username in the top right corner of the community.
