I'm surprised they don't have a timer running that pings themselves every N seconds. The ads all do that. Pinging themselves on visibilitychange or beforeunlo

I'm surprised they don't have a timer running that pings themselves every N seconds. The ads all do that. Pinging themselves on visibilitychange or beforeunload could also be helpful (though there will always be people who disconnect without warning, which is why you ping periodically if you care about time spent as a metric).