There is a lot of money to be made from raw data if you know what to look for in that data and how to use the information - and that can be done without invading anyone's privacy.
The bigger the network of people using a platform, the bigger, the more robust and the more useful the data is.
Take the recent Scottish referendum for example:
Now that we know the result, I guarantee you could mine the historical Twitter data over the last 2 or 3 months and find patterns in that data that exactly match the results of the numerous polls being taken over the same period. Patterns that were there before the surveys were taken
That may not be useful now, but once you have worked out what information in that data matched the survey data, you can then use that knowledge to predict results in future elections - or to help you work out where you need to go to have the most influence on people's views.
And that information suddenly becomes a very valuable commodity.
People are starting to figure out ways of mining this avalanche of data to predict revolutions, stock prices, currency fluctuations, shopping preferences - all very lucrative endeavours...
... there's money in them there datasets!