As soon as a new version of a project or one of its branches is released, an email is sent to the email address stored in your member profile. Subscriptions can either be made to the whole projects or to a single branch, in case you're not interested in development releases, for example.

An overview of which projects you're subscribed to is available through your personal homepage, in the middle of the right column. The select box you can find there can also be used to delete subscriptions, change them, or rename them (for instance, to include the reason why you've subscribed to this particular project).