In that example are you in competition with those other business' or are you going to provide them a service?
A subway giving a bread basket to a mcdonalds would be a bit weird/silly for instance, while a subway doing that to a dollar / pound store is sensible business practice.
A place like derpibooru already has forums, is what I'm getting at, so any people who use that are more than likely to just continue using that rather than this new place that barely has functionality.
Everyone on this site right now was presumably talked to by moony, is on board with the main idea of the site and most importantly _know each other_.
Newcomers wont have that, >>422
Like i said, it makes any newcomers from that site be instantly more comfortable with your own since they already know a staff member and how that person operates.
If it is just a "hey we exist" then yeah to do more than that would be silly.
Calling it 'outreach' implies differently though, sorry about the confusion i guess.