Overall attendance was probably down from what I saw last year, but that is just a guess. Getting seats to view the various matches seemed a little easier to me this year than last so again I'd say attendance perhaps was off a tad from last year. Then again, the general economy is sad to say the least, so fewer attendees than I saw last year is not surprising.
The average age of attendees again is hard to guess but my impression was that it was definitely an older crowd. I pegged it somewhere about 45 years old, perhaps a bit older. But that matches pretty much with what I see in the places I play pool at now. The Open isn't brimming with 20-something fans nor are pool halls or the pool tables at sports bars.
The stands were pretty energetic in showing their approval of good play or with giving big hands and shout outs to players they favored at particular moments. Shawn Putnam was a particular favorite.