After the big SSO update yesterday on TD.W, It seems ti be the only site I can log into physically, and GA.W uses my username from there now. My karma transferred from there to here...
I personally, do not like the thought of having my accounts linked together. I expected to remain an anon in both sites, this appears to be a break of anonymity.
The mods on TD have made their intentions clear that they plan on building a wider community to go head to head with reddit. Your username here had always worked over there too and vice versa, you just had to log in separately on the 2 sites.