Normally the commentary is good over on Hacker News. However, a post I read today concerning Google changing it's terms for API use caused a bunch of concerned posters to chime in with remarks about how it's their data, and if they want to give that data to Facebook, Google shouldn't stop them.
They make the assumption that Google is stopping them. This is simply not the case. You are free to share your Google data with your account on Facebook. You're even allowed to share your Facebook data with any other social network. Neither Facebook or Google prevent this (that I know of). However, you can't do this with their API without their permission.
Their is an expectation from hackers that data is only free if it can be easily accessed. However, the assumption here is that easy access should be provided by the company hosting the data via an API (Application Programmers Interface, a set of rules programmers can rely on to perform actions and retrieve data). Essentially, the thought is that by Google changing their terms of API use to prevent Facebook from using Google's API to extract data from Google about a user (with that user's permission, of course) is like locking the data to Google. This is simply not true.
The API is governed by Google, not the user. The user is free to do what he will with the data, but a business shouldn't be required to provide tools for others to grab that data if they don't want.
Users would do well to remember this. This is why efforts encouraging business to be more formal about opening up is important (and why measure like the GPL exist). What Google is saying is that if you want to use our API to retrieve customer data, you need to allow customers to send their data back to us if they want using your API.
If you want to use the tools we created, you have to pony up and offer tools to do the same.
As a user of these services, it's important you realize the differences and the reasons. It's your data, and you can choose how to use it, but it's the companies API, and they have the same right to use it how they see fit.