rjnagle writes: Here's a two part story I wrote on "Is your website green?" Part One examines the challenges of trying to estimate the carbon footprint of a webhosting service or a data center. Part Two examines how data centers try to improve their energy efficiency and whether the new Energy Star rating system for data centers (due April 2010) will change things. Some questions raised here include: 1)should businesses ask for PUE ratings from data centers before they use their services?, 2)how confident can businesses be about the numbers provided from data centers? and 3)is an Energy Star rating system helpful if it doesn't take into account a data center's overall carbon footprint?