Yahoo! Maps adds drag and drop rerouting
First up, after you change your route, a window will pop up to compare the distance and travel time of your new route with the original route. In other words, Yahoo! is not shy about telling you what a bad idea it is to veer from the directions it recommended in the first place. But you don't get the real-time street name and mileage updates that you get in Google Maps.
You can also easily remove a new destination just by clicking an "undo" button.