Cloud computing has replaced Web 2.0 as a popular IT buzzphrase. Nobody ever really knew what Web 2.0 was, but it sounded important, and a lot of small companies got lots of cash to "really important" Web 2.0 applications and services that were going to change the world, make a lot of money, and cure cancer. None of them made much money, and most of them made no money.
Despite the hype, Web 2.0 signaled a shift to much more sophisticated use of the Web, with much better Web-enabled interfaces. The secret sauce for Web 2.0 services and applications was broadband. Cloud computing takes these sophisticated Web apps and high speed data connections to the next level, where both desktop computers and portable devices like the iPhone are connected continuously to data and services hosted somewhere on the 'net (the "cloud").
Apple probably has the clearest vision for this; the company has provided nearly seamless integration of desktop computers and portable devices like laptops and iPhones/iPods with its MobileMe service. For $99 a year, you get "cloud computing," which means your various devices (e.g. desktop, laptop, phone) all stay synchronized more or less automagically--as long as you have some kind of high speed data connection attached to each device.
Cloud computing, despite the hype, is here, and will quickly become a business necessity, meaning communities that cannot provide their own businesses with the right levels of connectivity will suffer economically. And cloud computing, to work properly, has to work from home as well as from business locations, so residential broadband is business broadband. Finally, communities have to have broadband hotspots for business travelers, because those business visitors have the most urgent need for access to the "cloud" of data they use to manage their work.