Thought I'd dig this out of the Community 'Help' bit:
"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.
To subscribe a piece of content:
To view and manage your subscriptions:
just to add I'll put up a few pics here which may help. When clicking location firstly I get the first screen, as an example I'm picking Suggestions and Ideas- I would click the 3 dots in order to subscribe.