A common mistake made in consumer apps is that user acquistion is seen as the key to success. It is true that you need to acquire users, but what you really need is a good hook and then to keep those users. Instagram's hook was that they made filters and sharing easy amd free. People wanted filters and the sharing part was a bonus. However, once they were there, they naturally had to take part in the social aspects which made it far more engaging and therefore they stuck around. After that, it is only a matter of time before others joined in.

They used to, for at least the first 12 months, have quite a large 'download the app now' button.

This I believe was in the 'pre-comments on the website' era.

Couldn't find an image of this so might entirely be in my head.

Maybe nobody likes to be sold, but people won't download it if they don't happen to notice the download button either.

I imagine the likelihood for a person to notice the ad gets better as the button gets bigger and uglier, but on the other hand the percentage of people who don't download out of spite because the button is too big and ugly also gets larger.

There's probably a sweet spot there somewhere.

The thing I've never liked about this page is that the photo owner's username looks like a link.