This DoubleClick-sponsored research is based on a survey of retailers and agencies carried out in August and September 2008, with the aim of understanding more about the use of comparison shopping engines.

On average, retailers get 10% of their online sales through the comparison shopping channel and 43% of merchants surveyed say that this proportion has increased in the past year.

The report findings are divided into the following sections:

-) Use of comparison shopping engines (CSEs)

-) Budget and spending

-) Measurement and tracking

-) Ratings of comparison engines

-) Optimising feeds

Highlights from the findings include:

-) Some 21% of retailers surveyed are not currently using any comparison engines to advertise their products on, while a further 16% use just one CSE.

-) Google Shopping / Google Base is the most commonly used comparison engine, utilised by 63% of surveyed retailers.

-) The majority of retailers (59%) are not using online marketplaces to sell their products.

-) Most retailers (74%) manage their CSE feeds in-house, whilst only 13% use specialist feed optimisation companies.