[Note: This post was commissioned by Ashoka Changemakers' Citizen Media Global Innovation Competition.]

What is citizen media? This may seem like a silly question, given the context of the Citizen Media Global Innovation competition. But the concept is worth defining because it’s rapidly expanding.

Our media have been the fluid that connects our ideas since our earliest days as an articulate species. “Media” are any tools, mediums, or channels through which an individual or group creates and shares ideas. This is the process through which we form our conceptions of culture, power, justice, and community.

Our media were predominantly “citizen,” or individual, during the vast arc of human culture, extending over tens of thousands of years. Constrained by existing technology, almost all media — cave paintings, storytelling, song, and dance — were local and community-driven.

It is only recently that mass-produced ideas and broadcast-only media have emerged and grown into the dominant form. In some ways, the emerging, networked commons of citizen media is a hyper-connected version of the participatory media from which we began.

It’s certainly an exciting time to be an engaged citizen of the world. New technologies are creating media and platforms faster than bloggers and pundits can comment, annotate, and analyze them. There are countless new opportunities to manifest ideas and change our collective understanding of civilization.

Yet, for all the promise, we must be cautious and mindful as we move forward in creating the next innovations in citizen media. Great media theorists have long understood that media can be used todistract, disrupt, and manipulate.

We risk losing the ability to differentiate between benevolent and harmful applications as our media grow exponentially in number and complexity. Citizen media, despite the noble moniker, are not immune to these perils.

Much of the conversation around citizen media has centered on optimistic new tools for civic engagement. In pointing to the best examples of citizen media, many cite innovative platforms likeUshahidi and FrontlineSMS, or citizen-driven outlets like Twitter and Global Voices. But these represent only a marginal portion of the media being used by citizens throughout the world.

For a far larger percentage of the population — including those well-resourced and powerful members of our global community — platforms like Facebook and Google are the indispensable on-ramps to the human network. Their users number, not in the thousands or millions, but in the billions. They are the primary gateways to information about our governments, our culture, our politics, and our scientific achievements.

Yet, unlike technologies defined as “citizen media,” we barely understand how Facebook and Google control and manage the presentation of civic information. We need much more public discussion around the complex design decisions that drive the algorithms of these organizations.

Their elaborate calculations are arguably the most widely-used form of citizen media. Until we better comprehend how Facebook and Google control our flow of information, we’re unlikely to realize the potential of citizen media to bring communities together.

In Part Two of “Citizen Media in the Age of Algorithms,” I’ll discuss what is known about Facebook’s and Google’s algorithms, and examine their potentially negative consequences for citizen media.