comScore Announces Breakthrough Service for Measurement of Online Advertising in a Press Release, from comScore, highlighting Ad Metrix Publisher.  The reports will cover:

"…comScore Ad Metrix Publisher reports on:

• Ad impressions and reach for sites with display advertising
• Who is reached with these impressions via reach/frequency and GRP reporting for individual sites
• How impression and share trends change over time
  

For example - here' what comScore came up with where you cans see the differences between the audiences of the three magazine that is competing:

Competitive Display Ad Demographic Analysis for Selected Sports Sites June 2007 Total U.S. – Home/Work/University Locations Source: comScore Ad Metrix Publisher
Demographics	Percent Composition of Display Ads
	ESPN	FOX Sports on MSN	Yahoo! Sports
Total Audience	100.0	100.0	100.0
Gender
All Males	65.3	65.8	63.2
All Females	34.7	34.2	36.8
Age
Persons: 12-17	5.5	5.2	6.3
Persons: 18-24	14.5	8.6	14.3
Persons: 25-34	19.4	16.3	22.2
Persons: 35-44	28.6	26.6	20.2
Persons: 45-54	19.4	27.2	19.5
Persons: 55-64	6.3	9.0	10.3
Persons: 65+	3.3	3.5	4.2
Household Income
Under $25K	8.1	6.4	8.6
$25,000 - $39,999	5.9	8.0	10.4
$40,000 - $59,999	19.8	31.7	25.1
$60,000 - $74,999	11.2	10.7	9.8
$75,000 - $99,999	20.4	16.4	15.5
$100,000 or more	34.7	26.8	30.7