A fuckload. There are 160M active domains. Say 2% of them are news sites with tens of thousands of active articles, another 2% is e-commerce sites and forums wi

A fuckload. There are 160M active domains. Say 2% of them are news sites with tens of thousands of active articles, another 2% is e-commerce sites and forums with also tens of thousands of pages, and the rest have like 50 pages on average. So you have something like 154M sites x 50 pages each x let's say 200KB per page that makes it 1.540 TB of data. And for the rest 4% let's assume 20.000 pages on average by 2MB each, that gives another 250.000 TB. And then you add sites like YouTube which could easily triple the above numbers. You'll end-up with a million TBs at least. That's like 100.000 HDDs.