There are Raspberry Pi related questions at other Stack Exchange sites still being created, for instance:
Maybe we should advertise on those sites to make raspberrypi.stackexchange.com better known?
This has been proposed already. If you would like to look at this question and this follow up.
The issue we had was that the idea didn't gain quite enough traction, it was difficult to synchronize our clocks with the designer, there was not enough activity after the initial voting, all resulting in us never really finalized on a logo to be developed.
However, this is something we are still looking into and I have a number of people who I am currently talking to regarding logo and advert design.
I believe it's a good idea but probably not all questions will be appropriate here. Especially from StackOverflow.
Placing community ads on those sites is a great idea. Have at it!
But, before the topic comes up, please don't flag questions for migration to this site, it is strongly discouraged: Request to migrate a question to Raspberry Pi declined
Many of those are probably appropriate for migration. Especially since the more people we get here, the stronger our community will be. At least for the questions I've been looking for the answers to, the "official" forums are not terribly useful. The problem here is participation level.
I know that the foundation people are keen to keep people in "their" forums, but they aren't really conducive to either knowledgebase building or understanding whether a particular answer actually solved a problem or not - the regular forum-as-support problem which the StackExchange system has solved well.
Please be wary of claiming more topics than you can truly service.
For a topic that is at all technical and has parallels elsewhere in the embedded world, a poster is much more likely to get an answer grounded in facts and sound engineering practice by asking it on one of the other sites than asking it here.
Segregating out pi topics may make sense for things which are truly unique to this board or have sound community-knowledge answers, but it also means that far fewer experienced eyes will see the question - with the result that the ratio of speculation to fact in answers is much higher than on the other stack exchange sites where many of these questions could also fit.
