Why is that some facebook profiles show certain information to certain profile?

[Some]

I have two facebook account. One old and one new. So I like this girl and check her facebook profile and on my old account her profile show more information. Then I visit her page with my new account but It does not show as much information as the old one. I don't have her as friend on both accounts. Why is this happening?

[awesome on a stick]

It's likely one one of your accounts you have mutual friends. Security settings can be set to public, friends of friends, or just friends, so if you have friends in common, you will also see the information she has set to friends of friends.
Anyway, if you like her why don't you just try talking to her instead of stalking her facebook?