A report from NCC Group has revealed that retail sites which are filled with content from third parties, usually in the form of ads and other marketing materials, tend to take much longer to load than those that are more streamlined.

Visiting any site that offers safe shopping online is likely to result in being presented with some form of advertising, as retailers still rely on ads to help offset the costs of operating their online presence. But this study proves that it is better to strike a balance between generating revenue and offering visitors an agreeable experience.

On average, the sites which were at the faster end of the spectrum had just 83KB of extra content to load per page which, on a modern fixed line or mobile broadband connection, will make very little difference to the overall speed.

Conversely, the ten slowest sites which were analysed had a typical 618KB of data associated with third parties to load for each page - about seven and a half times more than their speedier competitors.

Previous reports into consumer behaviour online have found that most people will be happy with a site as long as pages take less than three seconds to load. For sites that cannot meet this minimum requirement, there is a much higher likelihood that visitors will get frustrated and head elsewhere to fulfil their needs.

Having a site which is not overburdened by ads is even more important in the age of m-commerce, since portable devices typically have slower connections than home PCs and so carrying out safe shopping online will take longer if too many ads are embedded in pages.

Mobile users also have data allowances to consider, so a more streamlined site will be quicker to access, as well as cheaper for customers to visit.