Google representatives are using blogs to defend the firm's proposed advertising deal with Yahoo in the face of stiff opposition.

Tim Armstrong, president of Google's advertising and commerce in North America, has posted two comments on his blog, in which he argues the case for the deal and explains the potential benefits to a sceptical marketplace.

In his first post, Armstrong revisited comments made last week by Hal Varian, chief economist at Google. Varian was responding to a study by SearchIgnite, which speculated that advertisers would not benefit from the deal at all.

Armstrong has posted a list of questions and answers designed to alleviate the concerns of any customers.

The first question, 'Will the Google-Yahoo agreement raise ad prices?' earns this response: "Neither Google nor Yahoo set ad prices. Ads are priced by an auction where an advertiser only bids what an ad is worth to them.

"The Google-Yahoo agreement will help advertisers convert more clicks into customers by showing more relevant ads on Yahoo, giving advertisers a better return for every dollar they invest."

Armstrong's second post continues this theme, tackling how the deal will affect the online advertising industry.

He argues that the deal will be good for competition, and will increase the opportunities for advertisers without giving Google and Yahoo any unfair competitive advantages.