Should I worry about my privacy if I use this "free" service? I don't really want them to serve me targeted ads based on the contents of my Google Drive. I don't know whether they plan to do anything like this, but still. Giving Google access to my files (in addition to my email, social network, voice mail, contact list, calendar, and reading preferences . .) makes me uneasy.
I've read that google's main goal for these free products is to increase the amount of time people spend online and not to monetize every bit of information that they come across. The more time people spend online, the more people see adsense ads. That's why Chrome and Android aren't spying on people's browsing habits like they technically could be, for example.
And to profile everyone to optimize those ads. People watch plenty of ads on TV. Google is rich because they have very special data used to price the inventory effectively.
There are a lot of companies I do business with that have sold my name to advertisers. Paying a company money doesn't mean they aren't going to make money off of you some other way too.
The idea of Google indexing my harddrive and using this data to better profile me has scary privacy implications. I will pay these services (gmail, etc.) I can opt out of Google viewing my data.