What is a number status? What makes it that?

Question

On eBay, when you look under SIM cards, many of them say that they're a gold status or platinum. I would like to know what makes a number have a different status, so I can tell what status mine is and my friends' and family's.

Thank you in advance to all who answer this question!

Answer 1

A memorable number.

Usually a sequence like 666777888 or 1234567 is involved.

Or several sequential numbers are sold together for a company or family.  

A bit like a personalised numberplate on a car - you either get it or you don't......