Robert_Charlton - 9:20 am on Feb 15, 2007 (gmt 0) I think this probably accounts for the anomalies I was seeing in numbers.
A PS to the above, from a disclaimer at the bottom of the Microsoft page...
The tools shown on the adlabs website are not yet in production; they are demos or prototypes of tools that we might include as production adCenter tools in the future. Additionally, the tools do not provide or display conclusive results; rather, they are designed ro produce anecdotal information that might indicate a trend or behavior that seems pertinent to an individual advertiser. Finally, the information and results persented here are based on a sampling of real audience data, and are designed only to demonstrate a proof of concept.
I think this probably accounts for the anomalies I was seeing in numbers.