It would really be useful for me when planning my cycling routes, to see how hard the hills are going to be, and to select good downhill mountain biking courses (a balance between overheating the brakes when too fast, and getting bored when too slow, lol)
OpenRunner does this by displaying the elevation profile in color, the more slope, the more red it is. This is neat, but the colors are difficult to distinguish. A better color map would be :
< 5% : green
< 10% : blue
< 15% : magenta
< 20% : red
> 20% : black
Also the elevation profile could be a little bigger for better visibility... Pixels are free ;)