I think he means his friends use location sharing apps, where you can actually tell people "Open this app/URL to see where I am right now.".

I remember installing a dating app one evening, and thinking "I'll look at it tomorrow.". Next evening, I opened and it said "This stranger and you were both at this subway station around noon!". Geezus Christ! I didn't even open the app the whole day! Uninstalled it straight away.