Agree with an earlier post... there is some flat-out incorrect info being thrown around in here.
All of the answers can be found in 20 minutes of Googling (hell, even Binging ).
I have been elbow-deep in credit score coding and calculations for most of the past 10 years now. Again, one thing to keep in mind is that no matter what any of the major 3 bureaus calculate your score to be, any given credit provider will probably use - as least partially - their own inhouse risk scores. So, not every company views your trade lines the same.
But, yeah, some of you guys need to go fact-check yourselves before you post your opinions as facts. Carry on.