Blogscoped reported this strange phenomenon: if you try to create a label named “buzz” in Gmail, it returns the message:
“Sorry, you can’t create a label named ’buzz’ (it’s a reserved system label). Please try another name”
According to the person who discovered it, the label wasn’t always reserved because he had used it before. Well, it is now I guess. Similar behavior were observed by other users. One had his label named "buzz", which he was already using, automatically renamed to "buzz0". Could this be because "buzz" is a namespace at Google?
Apparently, there are many more reserved or “invalid” label names on Gmail. Some of these are:
Have you discovered any other?