I hate those. Unless you're familiar with the whole team you don't know who qznc is. Git/hg/svn blame will tell you that more precisely. Inserting your name in the comment is only slightly less annoying than people insisting to put "author"comments on top of the file (or even a function)
If his username matches with his email, or if he uses the it consistently - maybe. But probably he wrote that note ages ago, someone else rewrote the function since then and left the comment because the content is still valid - ie. you're contacting the wrong person.
In short: metadata which is not updated automatically is most likely not up to date, and may be not correct in general.
