First of all, I hate dealing with troubles and problems, especially if they could be averted before hand. And tags will always become a problem of all SE sites. If you have come from any site you know that there's always drama about tags (we are already asking for some tags to be blacklisted) so lets prevent the problem before it becomes one. Here some ground rules:
Duplicate tags:
Apparently someone through that open-source was not enough and created floss and also suggested a tag excerpt. Please don't do this. If another tag already means what you are trying to tag use that tag.
Hardware tags
I expect some macair, iPod, iPad, blackberry, dell, et all tags. Remember that software depends greatly in the OS your device is running hence windows, ios, osx, blackberry-os are more relevant and useful tags. Nobody needs to know what hardware you have running your OS on.
Tag + space + tag
This is one of the most problematic... because people don't understand how tagging works. An user looking for a music editor will tag his question as music + editor = madness. Teach users about the use of the hyphen so those music becomes music-editor, music-player, music-production. The same applies to broader topics like: image, picture, photo, sound, text, etc.
I haven't found another example of something that is already happening but I presume other possible problems might occur in the long run.
