I guess OP meant that if you could see only a part of the web available to you as a logged in user of some service, then you couldn't build an index which globa

I guess OP meant that if you could see only a part of the web available to you as a logged in user of some service, then you couldn't build an index which globally scans a whole website, since it cannot log in. NOTE: well spiders could technically log in and index public shared stuff, but those services could forbid that via terms and conditions and sue any company violating them