While not nearly as impressive as either Vancouver's 16,500 or Seattles 28,000 (my numbers might be old), 10,000 STHs is still a very respectable amount considering that some MLS teams struggle to even hit those numbers in total. Also, and I don't know about you, but I've yet to see any serious media blitz campaign for the Timbers season tickets. If there is one planned, I'd be willing to bet we'll nab a few more STHs from that.
My own personal prediction is Portland will reach 14,000 STHs by the start of the 2011 season, although, at this point that's really just a guess. Still good numbers all around for the PNW rivalry set to take off once again in 2011.