show/hide this revision's text 2 send mail! shazam!

This sounds like something that can be achieved by writing a plugin:

Implement IPluginBugCommit. If a case is edited and the tags have been changed, look to see if a particular tag has been added (or removed?) and then send out notifications using CMailApi (plugins can't send email now, but will be able to soon)available as of FogBugz 8.0).
show/hide this revision's text 1

This sounds like something that can be achieved by writing a plugin:

Implement IPluginBugCommit. If a case is edited and the tags have been changed, look to see if a particular tag has been added (or removed?) and then send out notifications (plugins can't send email now, but will be able to soon).