I don't know if it's actually growing that fast anymore. We went from not much on the web 8 years ago (just info websites mostly and a couple Xanga & MySpace pages) to everything having a website (unless you're in Guam like me). I mean it'll grow by a factor of 10 once more, but I don't think there's gonna be more URLs than people on the Internet. Once every person, business, club, or product has a webpage it has to slow down and I think the developed world is reaching that point.
Then again, there will be a ton of growth over the next decade from the undeveloped world as every business adds a webpage. Still...I don't think we'll get over 3 billion URLs in the next 8 years and I don't think it's growing at an exponential rate--just linear.
The more interesting info that wasn't included is bandwidth. I think 30% of that bandwidth is pirating, 50% is streaming media, and 25% is everything else. What quantity of data gets transferred in 60 seconds? My guess is about 50TB a minute--90% used up by 20 million people downloading or watching video at any given instant. I have no idea what the actual figure is, but I would like to see it more than social networking stats.