Example would be invisionfree forums (The same forums used here). Forums that do not forward their address (which is why you see the URL forums.passwordmaker.org here) all use invisionfree.com/fourmname are their URL (i.e. invisionfree.com/passwordmaker). If you sign up for multiple forums and only use the domain invisionfree.com, each time you login you are asked which account to choose from. Romeo is saying to put more information in the When URL contains field to avoid this (i.e. invisionfree.com/iFusion etc.)