AOL hopes to boost its online advertising business in Europe with an offer to buy TradeDoubler, a Swedish provider of online marketing and sales services, for $900 million.

TradeDoubler's services include hosted tools that help customers simplify the creation, management, analysis and optimisation of online marketing and sales activities.

The acquisition will complement AOL's existing European online advertising effort, which is currently based on services from, a company AOL bought in 2004. operates a display advertising network in the US and eight European countries. It also offers search engine management and lead generation services.

Combining and TradeDoubler will offer advertisers a comprehensive range of marketing services and offer publishers more ways to make money in both Europe and the US, AOL said.

TradeDoubler's board recommends the offer but shareholders still must approve it. The deal must also receive approval from competition authorities. The companies expect the acquisition to close in February.

The proposed acquisition follows a change in strategy for AOL. The company recently sold off its ISP (internet service provider) businesses in Europe with a plan of offering its content services for free, supporting the business with advertising. AOL is also offering to manage online advertising sales and supply editorial content for ISPs' portals.