I think much of the value can be gained by collecting the data with some kind of differential privacy noise added to keep it from being traced back to any given

I think much of the value can be gained by collecting the data with some kind of differential privacy noise added to keep it from being traced back to any given user. But obviously data collected in this way is less useful--it may not matter, given diminishing returns, for services with enough scale, but yeah these techniques can make things harder for smaller services.