It needs to be said that Google and Facebook are perfect, no-brainer advertising platforms. Mass audiences + natural use behaviors that can be monetized via ads + user analytics and segmentation capabilities = beaucoup advertiser bucks.

But it's a mistake to look at a typical startup and assume there's some sort of magical "monetization switch" that can be flipped when sufficient scale is achieved. If your platform isn't a natural fit for advertising, or for other forms of monetization, then monetizing is anything but easy.

Scale isn't sufficient. It's necessary in a lot of cases, but in and of itself, it doesn't guarantee anything.