Today searching for
jquery dynatree slow in IE lead to a result from http://facebook.stackoverflow.com/. Checking further, this has all the facebook posts.
So, are there such more sub-domains? First I thought the top tags would be having this feature, just doesn't seems to be there as I tried http://java.stackoverflow.com which is not present.
I also envisaged that this might the featured/sponsored tag that get the sub-domain, but even that is not the case as per my observation for another sponsored tag
I have been here for a year and never came across this site. I also don't see a link to this anywhere or a relevant blog post for this.
Would be great if someone could throw some light on this.