The rise of Facebook as a truly mainstream social network was a big story this year. An interesting question is, how much of Facebook's success was directly related to its loosening of privacy controls at the end of 2009? That move created both a backlash and a huge bump in users as 2010 unfolded.

The issue of privacy has come to the fore again this month, with the swirling controversy around WikiLeaks and previously secret government cables. From Facebook to WikiLeaks, Google Street View to an app called I Can Stalk U, 2010 has been a tumultuous year in online data privacy. Let's look back at some of the major privacy stories of the year.

Facebook's Privacy Controls

In December 2009, Facebook announced a significant change to its privacy settings. Previously, most of a user's information on Facebook was private by default. That was the guiding philosophy of Facebook when it launched in Harvard's dorm rooms in 2004. In December, a large swath of the average Facebook user's data was made public.

Your name, profile photo, gender, current city, networks, friends list, and all of the pages you subscribe to, became publicly available information on Facebook at the end of last year. Later, in May, Facebook reluctantly reversed some of those changes. While the default setting for most content published on Facebook remains public, control over a few key settings were shifted back into the hands of users. Notably, the ability to hide your friends list and list of interest pages from the public.

According to Facebook CEO Mark Zuckerberg, sharing information is the norm on the Internet nowadays and Facebook's privacy changes were a response to this. "If people share more, the world will become more open and connected," he wrote in a guest article in the Washington Post. What he didn't say is that open data is also easier to advertise against. So, many accused Facebook of abandoning its core principles in pursuit of profit.

Other, more "open" social networks have been created to provide an alternative to Facebook - the most promising being Disapora. However, at this stage the 'open' alternatives are a very minor threat to Facebook's dominance in the social network market.

WikiLeaks

The most disruptive organization to privacy over 2010 has undoubtedly been WikiLeaks, the whistle-blowing website run by Australian Julian Assange. WikiLeaks has sought out and published thousands of previously secret government documents. It has become a new form of media company, with its so-called "scientific journalism" model and quest for radical transparency in government operations.

WikiLeaks has created a sharp divide between those people who believe that governments need to be able to carry out important diplomatic work under a cloak of secrecy, and those people who believe that freedom of information extends to what governments are doing on their behalf. Critics have argued that WikiLeaks has endangered lives, for example U.S. citizens fighting in Iraq. Proponents of WikiLeaks have argued that the system of secrecy needs to be disrupted in this manner, in order for true democracy to prevail.

WikiLeaks is nothing if not a product of its era. As our own Curt Hopkins summarized this month, "WikiLeaks, the site and the group behind it, could not have happened until the social web did. Leaks have happened for decades but the penetration and the mass of documents only became possible recently. Websites, email, wikis, blogs, microblogs and social networks created a network of avenues for leaks to come in and to spread out again."

Google's Privacy Woes

As the Web's dominant search company, Google knows what most of us search for and what we're clicking on. So privacy questions about the company are inevitable - and they were plentiful this year. From the flubbed launch of Google Buzz (many users objected to the integration with Gmail) to the roaming Google Street View vehicles snapping photos of people without their consent, Google was hassled and harangued by users - and multiple countries - about privacy issues this year.

Even Google's popular mobile OS, Android, attracted criticism. A study by university researchers found that some Android applications were transmitting private data to advertisers - often without users' knowledge. Google's response was that it was not an Android-specific issue, but one that affects all software.

The Dangers of Location Apps

Foursquare, Gowalla and similar apps took the tech world by storm this year. From a privacy point of view, it's ultimately up to users to take precautions when they are 'checking in' to locations. Sites such as the short-lived PleaseRobMe.com (which, as the name suggests, highlighted when people were away from their homes) showcased the dangers of publishing your location data to the Web.

These concerns also extended to services that allow geo-tagged content, notably Twitter. In August we reported on a site called I Can Stalk U, which alerted us to the dangers of geo-tagged photos shared from your smartphone to social networks like Twitter.

eReaders & Privacy

As we wrote earlier this month, eReaders have been one of the biggest trends of 2010. The EFF recently released a guide to the privacy policies of eBook providers, from Amazon Kindle to Google Books to the Internet Archive.

You may not realize that both Amazon and Google log the books you buy or download, plus the pages viewed. There are benefits to this, for example Amazon can give you better eBook recommendations based on the data it tracks about what you've previously consumed. But this highlights a continuing theme of the privacy debate: to get better recommendations, you have to give up some of your privacy. Expect this to become a more prominent concern next year, as personalization and recommendations become key features of mobile shopping apps.

Privacy Controls in Browsers

Web browsers are a very competitive market, with Firefox, Microsoft Internet Explorer, Google's Chrome, Opera and others all scrambling to provide better features than the others. Privacy controls are now one of those key features in a modern web browser. Microsoft's latest browser version is Internet Explorer 9, which recently got "tracking protection" for better browsing privacy. The tracking protection will be an opt-in feature for users to identify and block certain forms of website tracking.

Conclusion

As you can see, it's been a very busy year on the privacy front. As certain companies gain more power (Facebook, Google), the Web community at large becomes more concerned about what they do with all of our personal data. As for WikiLeaks, it's too early to tell what the ultimate outcome will be. But at the very least, WikiLeaks has shaken up the notion of privacy in government communications.

Let us know in the comments what privacy issue has gotten you worked up this year.