From what I can tell, they are not the same people. As for not having the same ip at the same time, this is true for most isps... except for AOL. Being the biggest isp in the US, you would think they will have hundreds of thousands of ips, but instead, they use proxy servers so those people end up sharing ips. My guess is that they are caching the content on local servers rather than fetching new pages all the time for all the users.