That's literally what they did for years until taking a16z's money...

They did it by building a community around the non-reddit related traffic. Basically redditor's would share imgur links outside the reddit ecosystem (Facebook etc), then other people would visit imgur directly instead of going through reddit. These secondary users are monetizable.

Imgur had to eat the costs of supporting reddit's hotlinking (though not all reddit posts are hotlinked) but that was more or less imgur's "marketing budget."

Datamining. What FB is doing. Sell the info.

Data mining what exactly? Unless you know what in the image, it's hardly interesting that a user with browser fingerprint X viewed some image with a random hash or name.

Sure it is, you can track the site it was hosted on and follow the fingerprint around the web. The image content isn't the juicy bit.

If I can see you viewed an image referred from /r/woodwork I might offer you some woodworking tools and drive up the conversation rate of my advertisements.

> The image content isn't the juicy bit

It is. The wealth of images alone, the sheer amount, from memes to vacation pics is worth so much now that image recognition is taking off.

I was perhaps too dismissive, it is certainly full of information. But I mostly meant for the moment the information most likely to be gleaned will be from referral links.