Combine multiple words into single-words, space to separate up to 5 tags (python c# ruby)
That's nice and compact, and I think the meaning is clear enough to native English speakers. However, I'm getting the impression that some of our non-native English speakers don't get that "single-words" means "a single word composed of the multiple words, separated from each other by hyphens".
I also think we could use a brief description of the purpose of tags - say they should be directly related to the question, and that they are used to categorize questions for easy search, etc. Someone who tags with "distinct ip addresses" is not understanding this.