I use both the Runtastic road cycling app and Strava. I don't feel I'm giving up any privacy with them, but to each their own. Only friends on Strava are people I ride with in real life, and I just have a handful of friends on the Runtastic app, and I don't think any of them actually use it. It's just a good way for my wife to keep track of where I am on long rides because it tracks me in real time. If I thought that was giving up my privacy I'd turn it off.