How’s this for timing? On the eve of F8, the Washington Post reported the billionaire chief executive of WhatsApp, Jan Koum, is planning to leave Facebook. He sold the messaging app to Facebook for more than $19 billion in 2014. Mr. Koum, who also reportedly plans to leave Facebook’s board of directors, apparently clashed with Facebook’s executives over its strategy to share data across Facebook’s platforms and its end-to-end encryption policy. You might remember WhatsApp co-founder Brian Acton left the company late last year, then quickly endorsed the #DeleteFacebook campaign. Both Mr. Koum and Mr. Acton weren’t the biggest advocates of advertising, writing in a 2012 blog post that ads were a “disruption to aesthetics, an insult to your intelligence, and the interruption of your train of thought.” (Tell us how you really feel!) One wonders whether, without WhatsApp’s resistant founders, Facebook may now find it easier to introduce ad products to the messaging app. Indeed, the WSJ reports Mr. Koum’s departure followed an internal debate about introducing adsto WhatsApp’s “Status” feature.