[filoleg]

>Maybe it should only count as online if you're actively using the app instead of having it open in the background

Not sure about desktop clients and not sure about what you mean by "open in the background" in this specific case, but I can answer this for mobile WhatsApp apps specifically. For those, it only tracks when you actually have the app open in your main view.

More specifically, if you just have the app in the background while using some other app, it doesn't count as online. If someone sends you a WhatsApp message and you receive a notification but don't open the app itself, it doesn't count. Only when you actually open the app is when it shows you as being online.

Personally, I agree with you that the simplest solution that would already resolve a ton of those issues is to simply only display your "online" status to those who you have added to your contact list (instead of to literally the entire world).