There was never a deliberate effort from TC to ignore StackOverflow, I linked to it in some of my posts there.

IIRC we simply were not in the loop on their news, announcements or tips.

A lot of the TC'ers use Quora which is why it is mentioned a lot, but in TC dev we were definitely big fans of StackOverflow, its just that the full-time writers didn't use it or notice it as much.

If you look at Techmeme, you can see that StackOverflow hasn't been getting much attention from the usual tech blogs:

http://techmeme.com/search/query?q=stackoverflow&wm=fals...

I figure it is for the same reason - they weren't actively reaching out to the tech bloggers and instead using their own blogs for PR. Still worked out well for them :)