* "What is this site about?"
* "What are best practices here?"
* "What kind of questions are on topic?"
These are some of the questions that should be easy to get an answer for.
I suggest that the main site view top bar gets an [About]() link on the left, next to the site name. It should go to a special Wiki post where the community in question writes a brief intro to the site, and link to various relevant Wiki posts.
Update Feb 16 2020: this is now available with the (experimental) new header navigation.
Currently, you can only see it in action if you have access to the Code Golf beta, but other communities can add 'about' pages on request.
Yes this would be very useful, though it may not end up being a simple link in the header because we are currently rethinking site navigation via the controls there. The site dropdown may become a more flexible custom control similar to the community dropdown on SE — and there would definitely be room for a dedicated link in there.
I've moved this on to [to a GitHub issue](https://github.com/topanswers/topanswers/issues/26) so work can begin and will update the post here when it is complete.