In less capable hands, using a bit of a ‘cloud’ motif to reference the more technical aspects of ‘the cloud’ could come off a bit ham-fisted, bit this site really nails it. I love the light feel of the white, rounded ‘clouds’. The splashes of color sprinkled about by the logo and various icons are just enough to keep it lively. I also think the hand-drawn (I’m assuming) logo is really great, it’s a perfectly friendly and creative treatment.