Because the way that TagMePlugin is implemented does not allow topics to be renamed, I had to remove it from my Dakar installations. I also prefer to avoid plugins that do not conform to PluginsApiPolicies, but the inability to rename topics without losing their tags is the real killer. I regret this, as it would have given some very useful functionality to my current project that I may not have time to implement myself. See TagMePluginDev for more on this subject. {1}
I don't think the concept is "one of a kind", but it's cutting edge in terms of social interactivity. I first tried to install it on an older TWiki installation, and it didn't seem to "take" for unknown reasons. Then I tried to get it working for some people who had installed it on the debian-under-windows distro, and couldn't. So I created a new Dakar (4.0.4) install and it worked fine there. I modified the code to implement a status="no" parameter so that I could get it to fit sanely into the PatternSkin toolbar (with some associated template and CSS changes). I'll move over to TagMePluginDev now..