Conversation so far:
what is a charity john mayer works for?
Mayer created the "Back to You" Fund.
what does this charity do?
focuses on fundraising in the areas of health care, education, the arts and talent development.
how does the charity raise money?
The foundation auctions exclusive John Mayer items.
did the charity earn a lot of money?
The auctions have been successful, with some tickets selling for more than seventeen times their face value.

Question: what is a type of philanthropy he works with?
Self-contained rewrite: What is a type of philanthropy John Mayer works with?