If you compare Facebook's uptime vs Reddit it is no contest. Granted, it isn't as widely used compared to Facebook Login, WhatsApp etc. but still it's impressive
One reason why this works so well is that there is often a monetary incentive on the referrer's side, in that they get paid some referral bonus if you get hired
This is one of the big reasons I've chosen to use Android where I can install apks on my device. Though I may not have the "blue bubble" of iMessage so many in the USA seem to associate with higher status
I think those interested in history and skeptics find it interesting to learn about how early Abrahamic religions were potentially influenced by Zoroastrianism