That picture with Facebook photos in comparison to the other major sites is impressive, I didn't realize they had that much dominace.

In other news, please, we haven't (IMO) solved the photo sharing/storing software problem. Snapjoy is close, but until I can have public photos, face (people) based grouping, and tags/event organization, it's not there yet.

That image is wrong and misleading.

Facebook: 140000000000 photos

Flicker: 6000000000 photos

Instagram: 150000000 photos

LoC: Wikipedia says 12000000 which is around the "Facebook has 10000 times more" so let's use that.

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Let LoC be a square of 1 pixel side lengths.

Instagram is 12.5 times as much. So the area would be ~13 square pixels, that leads to side lengths of 3.5 pixels.

Flickr is 500 times the LoC -> 500 square pixels -> square with sides of 22 pixels

Facebook is 12000 the LoC times -> 12000 square pixels -> square with sides of 110 pixels

As image: http://i.imgur.com/gCjqV.png

Ouch.

Image is definitely wrong based on your numbers but I'm not sure it's "misleading". Your picture also shows a complete dominance by facebook. The difference is big, but not important for the purposes of the article. Especially when you consider how poor humans are at determining amounts of things based on area (see the recent discussions on pie charts).

Interesting. Incidentally, this would make a great Fermi type interview question, to replace how many gas stations or piano tuners are there in the US.

Might be hard to estimate anything but the Facebook numbers, though. I would have a hard time estimating anything to do with the silver halide - annual consumption? Annual silver mining? etc.

I still don't understand how a Fermi question makes for a good interview question. How can you make reasonable estimates about something you know nothing about?

It's likely everyone you interview knows nothing about it, so it isolates logic and reasoning skills from previous knowledge. The accuracy isn't important.

I don't like those type of questions either, I said it would make a good Fermi question, not a good interview question :-) For some reason, some people love to ask such questions. I'd rather ask how to perform face detection on 1 trillion images.

Footnote 2 is incorrect, the civil war happened in the 19th century, not 18th :)

Appears to have been corrected.

Does this then make the case for the "yet-another-photo-sharing-site"?

I think the need for diverse photo sharing sites is only slightly smaller than the need for diverse word sharing sites.