It's never easy to know for sure where all the money in politics comes from, but media criticism is one area in which there is credible hard data available to anybody with an Internet connection.
Media criticism became a prominent political activity after decades of conservative complaints about liberal bias in mainstream media reporting led Brent Bozell to start the Media Research Center in 1987.
Bozell pioneered a rigorous form of point-by-point analysis of news reports that found an eager audience of millions of conservatives across the country and established Bozell as a powerful voice on the Right.
Nothing like MRC existed on the Left until 2003 when David Brock, a liberal convert from the Right who first became famous for his scathing critique of Anita Hill, started Media Matters for America.
Brock took Bozell's formula and put it on ideological steroids, vowing to "expose conservative misinformation" wherever he found it. The success of MMA also made Brock one of the most powerful activist voices on the Left.
The two men have become influential figures in their respective movements, and their organizations' budgets are something of funding weathervanes for political activism at both ends of the ideological spectrum.
MRC's most recently available IRS Form 990 shows contributions and grants for 2010 of $11.2 million and total revenues from all sources of $12.3 million. Bozell's organization employees 89 people.
At Brock's MMA, the most recently available 990 - for 2011 - shows total grants and contributions of $8.2 million and net revenues of $8.3 million. Brock's organization employees 113 people.
At first glance, the two organizations might seem almost equally matched for resources, but a closer look at the details of their funding sources and histories reveals some surprises.
MRC has received more than $27 million from 622 granters since 2000, according to FoundationSearch.com. That compares to 371 grants worth more than $29 million for MMA for the same years.
The vast majority of grant purposes listed for MRC's donors are for "general purposes" or "operating fund." Here and there are references to "bringing balance and responsibility to the media," or "for instruction and training activities."
But references to grants made to MRC for specific campaigns or initiatives are all but non-existent, with $50,000 grants in 2004 and 2005 from ExxonMobil for "climate change and environmental issues" being the notable exceptions.
A very different picture emerges from MMA's donors. Over and over among the 371 grants listed, grant purposes are described in terms that bear little apparent connection to media criticism.
The Ford Foundation in 2011, for example, gave MMA $595,000 "for an initiative to expose instances and sources of hate speech and violent rhetoric and to combat net neutrality misinformation."
Also in 2011, the Ford Foundation gave MMA $466,466 "to develop, test and disseminate winning messages on open Internet access and train media experts and young advocates to be effective messengers for open access and net neutrality."
The Joyce Foundation made $200,000 grants to MMA in 2010 and 2011 "to support a gun and public safety issue initiative."
The Stoneman Foundation gave MMA $150,000 in 2010 for "economic & fiscal policy progressive talent initiative training."
Another $150,000 was given to MMA in 2009 by the Unbound Foundation for the "Immigration Initiative (Immigration Monitoring and Research & Immigration Progressive Talent Initiative)."
And in 2006, the ARCA Foundation gave $50,000 to MMA "to support a Religious Broadcasting Project to expand the monitoring and fact-checking of religious broadcasts."
This difference in the reasons for which donors support MMA and MRC may be partly explained by their official purposes.
Countering "conservative misinformation - news or commentary that is not accurate, reliable, or credible and that forwards the conservative agenda" is MMA's reason for being, according to its website.
MRC describes its mission on its website as being "to expose and neutralize the propaganda arm of the Left: the national news media."
Thus, MRC focuses on how liberal bias shapes news reporting by journalists, whereas MMA seeks to counter "the conservative agenda" wherever it appears in the media.
In other words, MRC looks at how the news is reported, while MMA looks at what the news is reporting.
Mark Tapscott is executive editor of the Washington Examiner.