Forgetting the commas on the tags and ending up with one huge useless tag

I don't think I've ever made a huge tag like but sometimes I've made a typo and wished I could change my tag. That would be a good feature: "edit tags." I actually like the comma separation as it makes multiple word tags easy. Some sites use space separation instead so if you want to use multiple words as a tag you have to combine them likethis or like_this which is visually kind of ugly.