Scroll Wheel Zoom

Google, Yahoo, and (Microsoft) Live Maps all use the scroll wheel in a way that is generally unexpected on the Web.

Rather than scrolling the page vertically (in the case of some mice also horizontally), the scroll wheel zooms the map in (when pushing the scroll wheel forward) and out (when pushing the scroll wheel back).

It's a handy feature, but takes getting used to at first. Meanwhile, Mapquest seems the laggert, with its map retaining the "traditional web" use of the scroll wheel.