I believe they do header bidding for their own demand, but you can squeeze more revenue out of your traffic if you learn to manage your own headerbidding stack. Take a look at prebid.org and checkout the r/adops reddit. You might find some inspiration there.
Graffiti typically means "illegal", so that's why the headline sounds outrageous. 5 Pointz was more of a "graffiti museum", with substantial cultural significance. It was a nice piece of news to see for a change. I was heartbroken when they whitewashed that building.
For anyone that's interested in this, I'd like to recommend an awesome documentary called Vigilante Vigilante. It's about anti-graffiti vigilantes that take it a little too far.
Laugh him out of the room. The guy is pulling in $15k/month from the job. Some equity might certainly be in order, but definitely setup a standard vesting schedule with a one year cliff. 1%-5% equity for an early hire makes perfect sense at your discretion.