To download the complete version of "The Story So Far: What We Know About the Business of Digital Journalism," a new report on digital news economics from the Columbia University Graduate School of Journalism, click here.

• On digital platforms, it is often hard to make sure that advertising supply matches demand. Online editors frequently have a difficult time generating enough page views when advertisers demand them—or filling up that advertising space when reader traffic soars and ad demand is light. So news sites often need to run cheap ads, called “remnants,” that may get a tenth of the revenue their usual ads draw. Michael Barrett, the CEO of Admeld, a company that tries to increase advertising rates on sites with traffic prone to peaks and valleys, says that some of his clients view the situation “like seats on an airplane. They don’t want to fly the plane with any empty seats.”

Impact: Because the cost of creating each additional page is close to zero, media companies can have a wide range of prices, charging the highest rates for the most desirable times, placement, and audience. But all those unpredictable page views exert constant downward pressure on ad prices.

• Advertising is transformed in a digital format, and not always for the better. Some journalists may not realize this, but many of their readers and viewers see advertising as useful and entertaining. Indeed, access to advertising is another incentive for people to buy magazines and newspapers or listen to and watch broadcasts. But the appeal of online advertising is often diminished by its format. A small, rectangular banner ad conveys little useful information—certainly less than an insert in a newspaper or a glossy ad in a fashion magazine. To get useful information from an online ad, a reader often must click and head to a new site, something people rarely do. And the more intrusive forms of online advertising—such as “roadblock” messages that take over the entire screen for a few seconds—upset the user experience. Some digital companies are bringing content value to ads, but they tend not to be news media. Google became a powerhouse by tying advertising directly to users’ search queries. And Groupon, which attracts readers who are looking for online discount coupons, has become successful with witty come-ons and obvious value. Groupon has expanded rapidly into hundreds of markets and has turned down a $6 billion offer from Google.

Impact: Digital provides the ability to target advertisers’ messages and better metrics to determine impact. But users find that many digital ads on news sites convey little information and value.

• Digital platforms provide another way for advertising departments to attract new clients and retain old ones. For salespeople who don’t feel they have enough arrows in their quiver, online and mobile can be a way to get a reluctant advertiser into the fold.

Impact: Media companies can bolster more profitable legacy sales in traditional media by adding digital, and in the process, can move their clients to newer platforms. But deals that combine legacy and digital ad sales make it difficult to determine how much revenue is truly attributable to new media. At some companies, half of digital sales have been “bundled” with print or broadcast, and the way those dollars are apportioned can be largely at the whim of the accountants, rather than being an accurate reflection of the value of the ads.

• Many efforts to get readers to pay for content have been fitful, poorly executed and motivated more by ideology than economics. Only a few publications have had a successful, long-term plan to get readers to pay, and even fewer have done it in a way that genuinely increases online revenue rather than simply protects their traditional businesses. Was free content journalism’s “original sin”? Perhaps, for news organizations must now ask readers to start paying for material that has been free for fifteen years. Meanwhile, pay-per-article schemes, such as the one proposed in a 2009 Time cover story by Walter Isaacson, haven’t caught on for journalism. Unlike Beatles songs, news stories have little lasting value beyond a single use.

Impact: Users have unlimited access to most content, and publishers have unlimited access to most users. But circulation revenue, one of the mainstays of the traditional media business, has withered. And one of the methods that advertisers have used to judge audience quality—willingness to pay—has evaporated as well.

Bill Grueskin, Ava Seave, and Lucas Graves are the co-authors of "The Story so Far: What We Know About the Business of Digital Journalism." Grueskin is dean of academic affairs at the Columbia University Graduate School of Journalism. Seave is a principal of Quantum Media, a NYC-based consulting firm. Graves is a PhD candidate in communications at Columbia University. For further biographical details, click here.