Google didn't invent online maps, but in case you don't remember, everything stunk before them. As far as I remember, Google was the first to use AJAX to make the maps speedier as well as more intuitive and pleasant to use. MapQuest had to reload the entire page if you wanted to move, and the UI was worse to boot. You couldn't click and drag to pan; you had to use arrows to move some predetermined amount left, right, up, or down.
We have them to thank for why MapQuest and others (which have caught up, at least in UI) aren't so horrible today. Apple probably would have figured it out eventually if they made a Web-based version, but Google had this back in, at least, 2005.