LONDON: In the four months to 30 April 2007, online display ads for Microsoft dominated UK websites, reports Nielsen/NetRatings' survey of 16,300 web campaigns. In April alone their number grew year-on-year by by 32.6%, from 5,763 to 7,641.

Primarily promoting the launch of Windows Vista and its by-products, the software titan topped the list with 104 discrete marketing propositions. Another US computing colossus, Hewlett-Packard, took second place with 75 campaigns trailed by O2, Fidelity Investments, Dell, Orange and BSkyB.

But underscoring the medium's heterogeneous nature, the top twenty web advertisers between them took only a small slice of the online ad cake - just 7% of all campaigns.

Of the top-scorers, six were in the technology sector, four in communications, four in financial services plus two e-tailers.

Says Nielsen internet analyst Alex Burmaster: "While it's not surprising to see technology and communications brands embracing online advertising, many will note how the finance sector has an equally keen appetite for advertising on the web.

"What is also really interesting is that, unlike other areas of online, advertising isn't dominated by the few. The top five search engines, for example, account for 96% of all searches, yet the top five advertisers account for less than 2.5% of all online advertising campaigns."

Data sourced from BrandRepublic (UK); additional content by WARC staff