The company I work for makes the majority of it's income through online advertisers. We regularly audit our figures with ABCe for sales purposes, but a lot of media buying agencies have started to use ComScore. The dilema we have in the UK they currently have a sample of 80,000 users, which they inflate to the estimated online UK population of almost 18 million. Now from this you can see that a sites audience could be massively over or under estimated. Also it 95% of their sample are home users, this does reflect in their stats, as AOL usage is massive. I am unsure of the actaul figures for AOL usage in the UK but it can't be near what they quote. The result is that our figures are actaully smaller on ComScore than they actaully are and some of our competitors have hugely inflated figures. Anybody know how there system works, do the users have an application on thier pc that records all requests or do they all go via a ComScore proxy of some description. Apparently this is big in the US and it seems that the UK media buying agencies are becoming more trusting in it. So any info / help on how the systems works would be greatly appriciated.