Is it possible to tag TeamCity builds using service messages or some other programmatic way from a build step maybe...?
How can this be done?
See also the following stackoverflow discussion:
Programatically pin a build in Teamcity
Moreover, since there were two open questions on stackoverflow and I had the same problem, I wrote a TeamCity plugin that solves it:
https://github.com/echocat/teamcity-buildTagsViaBuildLog-plugin