Inspired by that Avril thread..

When can a artist be considered a A-list artist ? I pretty much think that A-list artist have to be relevent in the music world like Gaga, Beyonce, Rihanna, Katy and Britney. So are the A-list artist the "It" artist ? If so that means that Christina, Kelly and Avril are B-List artist cause lets be honest they aren't as relevent as before.

So can we say that A-list artist are the ones who are the "IT" artists at the moment
and that B-list artist are the ones who had their moment ???

Discuss.