It's shareware, which means you can use it for free for as long as you like. However, I'm funding it out of my own pocket, which is pretty much empty at this point. So if you want all the features and don't want to be annoyed by reminders to register please pay the modest fee and help me to make it better and better. Upgrades discounted for current users of course. Oh, by the way, registered users will be able to embed EarthBrowser with their own content on their personal websites within the next several weeks.
I just wanted to say thank you to everyone who has been so encouraging to me over the past few years; my wife, children and friends. I couldn't have done it without you.