I always thought that if I deleted ALL cookies, I would delete the automatic sign-on cookies which lets one enter a website without having to type in your USer ID and Password over and over again.
Also, wouldn't it eliminate the cookie which lets me log onto my local bank website, or my Ameritrade stock account website??
Those are nice ones to leave hanging out there for some hackkiddie to find. Those are the ones you most want to delete. You can still sign on. You just need to reenter you PW and UN.
FYI, if you use a product like Webroot's WindowWasher you can specify which cookies to keep & delete the rest - quite handy..
From your comment about cookies, I suspect you are running IE. Either Mozilla or Firefox will give you a built in cookie manager. Keep the cookies you want, allow others for the session only, and block the rest.