"As Veriac was saying , some of the things picked up are just cookies save on other sites . Therefore if you delete them you could be losing valuable info off other sites that you know and trust (like FlyOrDie)"
Well information in a cookie should not normally be of any important value (since cookies are always being deleted automatically and when the user clears cache, and some people don't even take cookies). The information that FlyOrDie uses contains information about your room history and a Jive timestamp for the forums. If you delete the cookie the only thing you will lose is the room history, everything else is restored when you log into flyordie.
Although I do recommend controlling the cookies that you store. Normally third-party cookies are blocked, which prevents cookies going into your computer from sites that you are not aware of. Also, in Internet Explorer it is possible to set cookie settings for certain sites, and I think there is a tool somewhere that automatically fills this list in for numerous sites that are known to contain malicious code.
Also watch out for your ActiveX controls (internet explorer) and Java applets, both are ways for people to gain access to computers and download adware/spyware/etc. so be sure to have some security settings set for them.