This is a repeat blog from April 1st. If you haven't seen this website recently, I strongly encourage you to do so. The numbers are not looking good. As a "demand" side measurement, the authors believe their reports are 1 calendar quarter ahead of traditional reports like "supply side" GDP.
I have had conversations by email with the web site authors. The weighted indexes reflect dollar amount of transactions. The individual sub-indexes are essentially the number of transactions. There is less money being spent in 2010 than the same period in 2009!