Actually some reporters have looked into this and it seems that it may not be about accounts that the Russian group have hacked but a list of account data that they have compiled from other hacking instances/data that's on the web. Much of the info is old and outdated. (i.e. the data taken during prior attacks on EBay, Yahoo, Target, etc.. - most of which is known about and that people have changed their info. for) Also the company that reported this is trying to make money from this by charging websites a yearly fee before they tell them whether they are on the list.

best thing to do, if your worried, change your passwords every couple of months (including and most importantly, the one you use for your email). Never use the same PW on multiple accounts, don't use "real words" and add capitals, numbers and symbols to your PW's.