After being DDOSed (cf. What just happened to Stack Overflow?) StackOverflow works again and Meta.SO obviously, as well. I also noticed, that superuser.com works. But all subdomains of stackexchange.com are still down (I actually did test only some of them).
Are there known reasons? Can someone tell something about a time span, how long this will last?
IS the actual problem now, that perhaps thousands of users continiously are pinging their favorite SE site?