I think a large part of the sites are the bits that only advertisers get to see or use - ie the bits that make the money. It is possible that the companies cou

I think a large part of the sites are the bits that only advertisers get to see or use - ie the bits that make the money. It is possible that the companies could be much smaller and cheaper to run if they dropped the ad-selling and the associated data recording and analysis infrastructure. But it seems to me that currently insufficiently many people are willing to pay for something like that.