Emily Parker is a former writer at The Wall Street Journal and the author of "Now I Know Who My Comrades Are: Voices From the Internet Underground." She is also a former member of the Policy Planning staff at the US State Department. Parker is currently working on a blockchain startup. The opinions expressed in this commentary are hers.

(CNN) Facebook is under fire for allowing a Trump-affiliated firm, Cambridge Analytica, to access the private information of 50 million users. Facebook did not inform those users that their personal data was being harvested in an attempt to help Donald Trump win the 2016 election.

This raises many disturbing questions about Facebook. For starters, why does one platform have so much control over the personal data of billions of people?

But this is part of a much larger story. Not long ago, a handful of internet companies threatened to overturn the old order. Facebook challenged traditional media. Platforms like Uber, Netflix and Airbnb disrupted taxis, movie theaters and hotels. Now, these once-rebellious upstarts have become extremely powerful, and they know way too much about us.

Emily Parker

People are getting tired of it. This helps explain why you keep hearing the word "blockchain." Blockchain technology, among other things, could potentially make platforms like Facebook obsolete. Many people know blockchain as the decentralized record of bitcoin (a virtual currency) transactions. It is the technology that allows digital money to circulate around the globe, without the help of banks or governments. In other words, blockchain cuts out the middleman, and this technology can be applied to many different industries.

Imagine if you, not Facebook, controlled your own data. Or if you could rent out your apartment easily and securely, without paying a cent to Airbnb. If readers could buy digital books directly from authors and filmmakers could know how many times their movies were viewed. Musicians would be able to keep better track of when their songs were played, and get paid accordingly. Taxi drivers would transact directly with passengers without Uber knowing everyone's location.

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