On GitHub you can use a git tag to publish a release announcement which will then appear on a release page (example) and release feed (example). If a developer has done this, you can subscribe to the feed to receive notification of releases rather than all commits.
Is it possible to do this on Bitbucket (hg and/or git)?
(There is an additional option to include binaries / tarballs in GitHub release announcements. I am not concerned with that feature or any others beyond a feed with announcement entries.)