Strava is easily my favourite social network (if one could even call it that). It's non-addicting and the more I use it, the better I feel and more productive I am. I've never ever seen an argument on it either. Its positive flow-on effects are superb.
The heat map "revelations" earlier this year was slightly fascinating but made me wonder how many of those writing or commenting about it have actually ever used Strava.
Disclosure: I don't "race" using Strava and use "common sense" to avoid taking risks, etc - the riskiest thing to health for most people these days are sedentary activities.