Let me first take StackOverflow as an example. After collecting a database with thousands of questions&answers SO can get many redirects from Google whenever somebody asks Google smth like 'Why this ... doesn't work in this way?'. So for external (non-SO) user it is pretty easy to find useful solution for his problem on SO.
Now let's take a look on CodeReview. Questions here are very specific and narrow (though answers may contain very generic ideas) and I do not see any way to find this site in internet if you do not know it in advance. And it corresponds with the question
how will we promote this site? because without it CodeReview won't be able to promote itself (opposite to SO which is self-promoting using Google for example).
It is pretty clear why this site is useful for CR-users: those who ask for code review may get some points regarding their code, reviewers can see ideas of other reviewers which also stimulates writing better code. But is this site useful for non-CR users? And do you see any scenario how external users will be able to find this site if they were looking for some solution? Or maybe it just doesn't matter at all?