Strava has acquired 3D mapping company FATMAP
techcrunch.comShameless plug: I'm working on a Strava like web app and I'm looking for Beta testers: https://cubetrek.com/static/join.html It's a hobby project of mine, because I wanted to build an app to track my hiking and skiing activities in a way I like it, including 3D visualization (I live in Switzerland, so it's usually always either up or down and that's hard to visualize on a 2D map) and easy comparison of past efforts on the same track.
You're more than welcome to try it out!
It looks like Strava has grown tired of paying Mapbox and is looking for alternatives.