Google Voice is a great service, one of the best things Google has released in a long time. Unfortunately, most casual web users have no idea what it is. Or more specifically, what it's purpose is. And in fact, there's even still some confusion amongst heavy web users about whether Voice is VoIP, for example (it's not — yet). So Google has today launched a series of videos to explain the service. The first (embedded below) is a simple overview, "What is Google Voice." The 11 others go into more detail about actual features such as the mobile app (as in, the one that actually works on the iPhone), how to block callers, sharing voicemails, personalized greetings, and connecting all your numbers to your one Google Voice numbers, among other things. You can find them all on this new YouTube page that Google has created (just in case you thought Microsoft were the only ones using YouTube for product promotion).