Bug authorization site "Classmates. Ru" or how not to do

The odnoklassniki.ru website has an amazing system of authorization and use of sessions. For example, here you can read about the surprise of people who followed the link in a post (And by no means go yourself!): Dolboeb.livejournal.com/1076635.html?thread=39293851#t39293851

And the cookies that this site is very interesting prescribes to you. Look - I personally did not like this garbage.

Interesting - who does sites this way?