I was really scratching my head about what the hell tags were when I saw this yesterday. I clicked around, read pages, mentions of tags all over but no explanation or alternate description of what they were. Terrible unless you're some marketer already using all these. As a web dev, I was mystified (realize now exactly what it is, but just never used the 'tag' word). Seems like a lot of work for a niche space/userbase that is heavily tagging content/etc