[tcmb]

Nobody has to stop using WhatsApp, the scenario described in the article can be prevented simply by changing the app's privacy settings.

[polote]

Wrong, if you deactivate the feature 'last seen at' it doesn't change anything because you can still get the same information with the feature 'is online now' and this feature can't be deactivated

[NasKe]

What count as "online"? Using the app? Does the web app also track that? I don't think this is disclosed by facebook, it would be nice to experiment to check it.

[Tijdreiziger]

AFAIK, having either the mobile app or web interface in the foreground.

[100ideas]

Can't a user just remain logged-in on a second device 24/7?

[jhasse]

IIRC you can't log in from two devices at once with WhatsApp.

[netsharc]

Did he mean change it client-side, or if WhatsApp the company changes this setting to allow more privacy (allow users to hide their status).

[slig]

AFAIK, it will display that the user is online (i.e: the user is using the app) regardless of the privacy setting.