[pas]

It's in the ToS, and it's their entire business model, that they do things you might like that makes them money, so you don't have to pay with money, you pay with data derived from the usage of their services.

I think it's not just your data. It's not completely theirs either. Your search history is very important from a privacy standpoint, but it's still just data about how a particular user account, session, IP address or browser GUID used their services. It's not data you have explicitly uploaded (let's say like you do with YouTube or Photos).

The whole problem is the infrastructure they have in place. It's not transparent, and thus we don't know who gets to drink from their firehose of [meta]data.

It's a very good and hard ethical question (problem) to judge this trade-off. (Short term gain for our civilization, since we get awesome services for free - as in the population just uses it and generates the data, so it's endogenous growth, - but in the long term we increase the risk of having to face an efficient totalitarian surveillance system.