Visual Studio Team Services now supports triggering a release, in team services release management, when a defined tag is available in a completed build. This helps you to filter a build or builds, to get deployed via the release pipeline, out of builds that are successfully completed.
For example a build that is tagged as RTM, would trigger a release while another build, completed successfully, but with no tag is not triggering a deployment. In order to say a release should only be triggered with a given tag, it should be defined in the Triggers tab of the release definition.