I am a little bit confused by the @username syntax in comments. It says that both @peter and @PeterSmith will work, which in my opinion should be changed to something more clear.

Does this mean I can call user Peter Smith by @peter or do I have to address him with his full username including spaces?

• My understanding is that going up to the first space in the username works, e.g. @Peter will work on Peter Smith but not on PeterSmith. Feb 23 '11 at 13:30
• @Qiaochu That would make sense. Nonetheless, I think you will agree with me that the explanation provided is confusing. Feb 23 '11 at 14:00
• Even @Mil is supposed to work. Feb 23 '11 at 15:32
• I would say that ambiguity depends on context.If we had comments by a Peter Smith and by a Peter Jones, a reply starting @Peter would leave the adressee not well defined (!), but if only Peter Smith cared to post a comment, where is the problem? Feb 26 '11 at 9:12
• @Andrea Mori it's not about ambiguity as you understood it. It's about the automized notification system. Feb 26 '11 at 17:47