Following the purchase of Doubleclick by Google and then Right Media by Yahoo!, the rush to buy up online advertising agencies and networks was joined by Microsoft at the end of last week. They paid out $6bn for aQuantive in the hope that they can retain some control over the potential online advertising revenue that is fast disappearing under the ownership of Microsoft's competitors. There's more on this story here.

The next big area for potential acquisition is now thought to be the area of web analytics, which can help advertisers measure their advertising traffic and add a new level of quantitative data to their online spend. Although search advertising remains the big growth area at the moment, the recent acquisitions of the big adserving networks heralds a renewed focus on the brand advertising sector and this is likely to result in a demand for more data on the reach and effectiveness of this activity. The New York Times recently published an interesting article on this emerging market sector.