I remember being the creator of the iis-7.5 tag with this question. Since then it has had 324 questions tag with it. Any idea?
EDIT: after reading the comments from the moderators, I feel this 'error' is unfair to users trying to tag content. I created the tag in good faith to match other naming conventions for iis5, iis6, iis7. Another user comes along and edits it (incorrectly) and my tag is thus deleted. Users will choose whatever tag shows up in the auto-complete list, and in this case my tag is now gone, and iis-7.5 shows up instead. I feel that this takes away part of the incentive to add tags to new content.