They used to just be an app, and now they have an ecosystem of products (Whatsapp, Instagram, etc.). I wasn't referring to the fact that they also run an advertiser-facing platform at all. I was just pointing out that they started as a single product and have expanded to being a larger platform, with all the network effects/benefits that such growth entails. That's great for them, at that stage.

But it doesn't make sense for all earlier stage products to try to become platforms. To me, the VC was showing a not-uncommon tendency to swing for the fences (or rather, to suggest that an undiversified startup founder should do so).