does YPN track the IPs of all locations you log into your account or just the initial one that you signed up under? I am paranoid to check anywhere that is not home because I don't want others clicking on ads on my sites where I've logged in...
I think they do track it but I could be wrong because they don't tell you that they do (maybe in their ToS or PP). Anyway, usually large businesses such as Yahoo! would most certainy track your IP address. And yes, you can login your account using someone's computer. Since it cannot remember the password (just the username) you should be save. However, just to be safer, you should not login checking the "Remember Me" checkbox and clear your cookies/sessions once logged out.