WebGL is now used in Google Maps to send vector graphics to the browser (a similar principle to the one Google Maps for Android works on). As a result, when zooming in or out the browser transitions almost seamlessly. According to Google Maps’ software engineer Evan Parker, “the maps are drawn dynamically with vector graphics, instead of loading individual map tiles” . Also, by dropping “Pegman” into the street the browser transitions between the map and street view much smoother.
Google has experimented with Web GL in projects like “All Is Not Lost” and “Three Dreams Of Black” earlier this year (note the domain names of the websites). You can see the official MapsGL announcement from Evan Parker and the ”Three Dreams Of Black” behind the scenes video which explains WebGL technology a bit after the break.