NYSE ticks/second = message sent to you of x bytes and processed:
May 2006 - 4,000/sec
Jan 2007 - 7,000/sec
Jun 2007 - 24,000/sec
That's about 500,000,000 ticks/day...
Which might be 5 or 10 or 20 GB sent over your internet connection...
To process in real-time every day.
A LOT of...