ID's like Hashes

[Opserty]

I don't see how privacy is related to a UserID number? How will a unique hash be any different from a unique number? Both of them are unique so both will point to a user in the end so there doesn't appear (to me) to be any gain in privacy. (A hash will just be longer and maybe letters or something).

I don't understand how its going to make it more private...

but if you could have the option between a number from 1 to endless, your nickname, and a random hash as your ID, which will give you the best feeling of privacy?

Just choose a totally random nickname? (I get the feeling you are misunderstanding the concept of "privacy"). The "UserID" is just an internal pointer that vBulletin uses to relate all data back to a user, if you change this to a hash what purpose would it serve? Everything would still point back to the user so that change seems useless.