By this I mean information in regards to posting comments that directly pop up in users' inbox using @Username, and details of the correct format if the username is split up into 2 words like "Namep1 Namep2"
I've been using these sites for a number of months now and I am still unsure if I'm doing it correctly because I can't find reference to it anywhere on the site, but I was told by 1 user that's what it does and have seen a number of other users doing it too.
Since this is already a site feature I think it would be useful if it was referenced on the site and not just passed around by word of mouth, which could result in chinese whispers style passing of information.