It was announced today that Google are now using site speed in web search ranking.

Google we’re obsessed with speed, in our products  and on the web. As part of that effort, today we’re including a new signal in our search ranking algorithms: site speed. Site speed reflects how quickly a website responds to web requests.

Speeding up websites is important — not just to site owners, but to all Internet users. Faster sites create happy users and we’ve seen in their internal studies that when a site responds slowly, visitors spend less time there. But faster sites don’t just improve user experience; recent data shows that improving site speed also reduces operating costs. Users place a lot of value in speed — that’s why they decided to take site speed into account in our search rankings.