Signup often means "become a member of [whatever.com]"

Signup may sound less harmful or less a big step than "Become a member"

So remember that as a Member in anything you are under those rules (capitalised 'Member' is different to 'member' also).

So if you sign up to American company you under that House's of Rules (including law over-looking all those rules).

Do be careful Neo.. America is very aggressive.

We could do with reducing the
'signup' (which is also an military-type term) and reduce support for aggressive people

(even if that would include reducing our own usage)