I got my name on this paper kind of by accident. I was a late arrival on the Vivarium project. Jay Fenton had been doing some very interesting work on programming languages for kids. He wanted to write something up for OOPSLA. I offered to help him.
I ended up reorganizing the paper enough that he offered to put my name on as an author. I felt a little funny, especially since the paper had been accepted with only Jay's name and I was the program chair and besides, I already had another paper in the conference, but I accepted anyway.
The next year, I was on the ECOOP program committee. We had our meeting in Paris. I remember eating lunch in the Xerox cafeteria. Next to me sat a bright, eager Ph.D. student. He began grilling me about the paper and the research behind it. Turns out his class had been given the assignment of figuring out how they would extend existing research, and the Playground paper was one of the three they could pick to extend. This was a shock, because I don't consider myself a scholar. Really I'm more of a talkative engineer. However, it was fun to be noticed.
Technically, I'm amazed at the prescience of Playground. Alan Kay was absolutely convinced that direct control structures, like Smalltalk's message send, would run out of gas and that “pulling” -style would come into vogue (even though the Internet apps call it “pushing”).