To make it more clear, here's the flag page/fly-out thing:
(Pardon the coloration, as I use a dark theme for the site.)
In the very top-most option, it has links to Unix & Linux, Super User, etc.
It's still in beta, and I'm not sure if that status matters, but Elementary OS has its own StackExchange site here and has had it for a while now.
Should Elementary OS be added to that dialogue?
It may make more people aware that it exists and may lower the number of questions we get about Elementary OS. Of course we can just ship them off to the Unix & Linux site, as we currently do. At the same time, it may be a better idea to send them somewhere more specific when the opportunity arises.
On the other hand, it may make absolutely no difference at all and the Elementary page is still in beta. It may also start a trend where we'd have to have the text changed every time another Linux distro gets a SE site of its own. That could end up rather verbose.