Currently running in Beta test mode, Google are testing video extensions that will be shown with their Adwords ads.

The plan is to have an "expandable plus-box" directly beneath the normal PPC text ad in which video extensions will play. Users will be able to watch the video before deciding whether or not to click-through. This sounds interesting for users, but the current cost of this service for advertisers is less appealing.

Once viewers reach the 10 second mark the advertiser will be charged the same maximum cost per click as if their ad had been clicked, regardless of whether it is clicked. So will this lead to a flurry of 10 second ads or are the search results becoming more and more cluttered, as with Google Preview?

Google has suggested that video extensions could be of particular use for product demonstrations, previews and trailers.

At present, there are no plans to roll this service out in the UK.