So I'm not sure if this idea has come up, but on Travel.SE we have very regular comments to new users, generally along the lines of :
"Welcome to Travel.SE. Currently your question is not a great fit...."
"Welcome to Travel.SE. You've asked a question as an answer, and as such..."
"Welcome to Travel.SE. You may not have seen our [faq]...."
and so on.
I can now type "Welcome to Travel.SE" nearly as fast as I type my name, and was wondering if there might be room or feasibility for custom templates for this...
Something like "Mod Menu"->Add Comment Template->"insert custom text"
Just a thought, not sure what others do about this or whether anyone else does tend to welcome new users, but I thought I'd see what people say.