Normally there's no difference, but if your password is saved in your browser, it's possible that in your list you have both druchii.net and
www.druchii.net but in each of them has a different account/password saved.
I had this problem once where I wrote my account/password but they used the saved password instead.
It's a possibility but it's hard to say. As I said, though, with or without the "www." should be the same, there's some few exceptions though...