The UK's top online advertisers 2009

The top 10 are:
1 - O2 - £15,189,000
2 - COI - £10,361,000
3 - BT - £9,213,000
4 - British Sky Broadcasting - £8,154,000
5 - Microsoft - £6,961,000
6 - T-Mobile - £6,582,000
7 - Orange - £6,370,000
8 - Virgin Media - £6,364,000
9 - Hutchinson 3G UK - £5,585,000
10 - Moneysupermarket Group - £5,281,000
Source: Table from Marketing Magazine, March 2010, using figures from Nielsen.
(The table shows the top 100)
Full statement on the methodology:
"Nielsen has improved the methodology used to work out the top 100 online advertisers for 2009. The new data is based on a Netview panel. Each panellist is given a meter and every time they view an ad online, it counts as one impression which is projected nationally. Previous surveys used a combination of figures from ABCe and declared information from the sites themselves. This tended to lead to inflated spend data. The new system creates a more robust methodology and removes the inflation factor. However, it means there is as yet limited comparative data with the previous year.
The figures are for display advertising and all figures are estimated costs based on a number of factors including rate card and industry discount factors. Details of the full methodology are available from Nielsen."