One of the questions was to talk about cross site scripting.
I described the basic concept and then mentioned how so many sites volunteer to be cross site scripted, by loading random scripts from multiple ad networks.
Some years ago I was working at Zvents on front end code for their partner sites. These were news sites who just loved to pull in as many ad network scripts as they could.
Those ad networks did not make my job easy. Here I was, trying to create a nice experience for our users, and robust across multiple browsers... And the ad network scripts kept breaking fundamental JavaScript features! A lot of my time went into reverse engineering their scripts so I could figure out how they were breaking things and work around it.
A pox on ad networks, I say.