In 15 years in tech journalism, I watched many companies try to drum up interest in the idea of services running on centralized servers and accessed by thin (or thinner) clients. The ideas went by a lot of names -- network computing, utility computing, grid computing, [fill in the initial here]aaS -- but the concept generally flopped, or at least was restricted to specific niches. But about five years or so, a new term arrived the covered many of the same concepts -- cloud computing, or, just "the cloud." (Here's IBM developerWorks trying to explain the differences in 2009.) Whether we were just waiting for the right metaphor or for better network connectivity, it's undeniable that the concept has truly arrived.