I just got back from the signing in Portland (well Beaverton). There were well over 200 people there, possibly closer to 300. I got there 30 minutes before the signing and introduced myself to the bookstore staff. The seats were already filled, and they let me give an announcement up front before Brandon got there to let people know what I was doing and to track me down to contribute to the scrapbook. I found a lot of people by eye contact in the audience and passed out cards (I printed them on cardstock, which worked well) and pens as needed. I had bought a set of gel pens before, which was a nice touch for a lot of the cards.
After my initial lap around the audience, I stayed by the table handing out tickets for the signing order. By the time Brandon got there and the signing began, I had gotten most of the the cards out and already gotten most back. A few found me during the signing itself, but interest in my project had wound down at that point.
I printed 3 copies of the pdf, totaling over 90 cards. I ended up with 52 cards signed (53 after I do mine) and I passed out something like 75 cards, so I had just about the right amount. Here are some of the cards that stood out.
http://www.17thshard.com/forum/gallery/image/365-scrapbook-cards-1/
http://www.17thshard.com/forum/gallery/image/366-scrapbook-cards-2/
http://www.17thshard.com/forum/gallery/image/367-scrapbook-cards-3/
http://www.17thshard.com/forum/gallery/image/368-scrapbook-cards-4/