Why are Equifax reported FICO scores different from site to site?

[Anonymous]

I just signed up for MyFico to check my credit score and found that my Equifax score was 642, I then signed up for CitiCredit watch and found that my Equifax score was 614. Why is there a difference? Which one will lenders see?

[Tuscani]

The difference is FAKO and FICO!

FICO (the score from MyFICO.com and Equifax) is the score lenders see and the one you care about.