I never heard of it.
No, I don't.
So many businesses (insurance companies for example) use it in their risk analysis procedures, I like to make sure I stay in the "excellent" range for my credit score.
And I have found that using an interest free offer to fund a major purchase to optimize cash flow and take advantage of "cash back" cards can knock 50 points off your FICO score for 2 or 3 months.
All the time. Good credit site.
Nope ! Never had a need for it.
I have, yes. Good site.