How about having a short link to other sites in the StackExchange network?
[site:superuser] displays as SuperUser
[site:cs] displays as CS
[site:area51] displays as Area51
(a better suggestion of minimal typing to link to other sites is welcome)
I often point users to other sites where questions (may) belong, but the overhead to linking to the URL is quite significant sometimes.
Also: It may be worth thinking about whether we'd want to use something like
[site:cs/something_goes_here] for CS/something_goes_here, though I don't think I'll ever use that format.
Note: Apologies if this already exists, has already been suggested or something similar has been declined. I'm not really sure how to phrase these things in square brackets.