What do Chemistry 101 or Introduction to European History have in common with Harry Potter and the Half-Blood Prince or the latest singles from Green Day or 50 Cent?
They're all bestsellers in their domains. Education experts often wonder whether bestseller status among college courses might provide lessons about educational markets and planning, just as popularity shapes entertainment and cultural products. Such speculation has grown with the advent of online education. Some argue that by making the most popular courses virtual, colleges can slash costs, helping to pay for low enrollment courses.
The alternative has been to raise revenues for low-enrollment courses by adding enrollment. This "add seats" approach has become more attractive in the new world of online education. Which alternative makes more sense for colleges considering online versions of some courses?
Cost-cutting advocates suggest that great efficiencies may result from delivering online a small set of popular undergraduate courses. Courses such as Chemistry 101 or Introduction to European History would have large enrollments and "basic" curricula. These popular courses illustrate the "80-20 rule" -- 20 percent of a resource typically generates 80 percent of the possible benefits. Popular courses may not even constitute 20 percent of the catalogue's contents, yet they often represent 80 percent of enrollments. If that 80 percent can be served through automated, virtual means, that should release tremendous savings, offsetting the cost of courses that don't lend themselves as easily or cheaply to virtual delivery.
Sales data on books and music tracks cast marketing and planning issues in a new light. Chris Anderson, editor of Wired magazine, describes a new phenomenon first noticed in Web-based retailing of pop culture products such as books and songs: Very low-volume sales -- typically associated with backlist items -- can add up over time to stupendously large total sales. Anderson calls these large totals the "Long Tail." In Internet marketing and flexible warehousing, Anderson says, the Long Tail results in aggregate possible sales that can rival or surpass the total sales of popular items. The more books or songs available for purchase, the bigger the market opportunity.
A conventional marketer might carve out space for known or likely bestsellers and concentrate on selling those units -- the 80-20 rule. Selling the 80 percent of products that appeal to the slimmest markets simply costs too much. But the virtual marketplace makes it possible to reduce overhead drastically. For the low marginal cost of adding non-bestsellers, a business can make major gains from trickle-like sales of an enormous, traditionally neglected body of products. Call it massive multiple-niche marketing.
In higher education, the Long Tail view suggests that an 80-20 rule overplays the importance and benefits of moving online the 20 percent of classes that draw the highest volume. If we can find effective, high quality ways to make bestseller courses virtual, there are good reasons to do so. But there is also a broad and deep market for all those smaller classes-not in the individual instances but in the aggregate. We know this because so many of those courses are offered by colleges and universities, and so many such classrooms are reasonably well populated. Surprisingly, the Long Tail perspective suggests that, with Web-based delivery, potential exists for great expansion in specialized subject areas, as long as the costs of instruction (course delivery) resemble or improve on current rates.
An important distinction separates Long Tails in pop culture from those in higher education. It's possible to cut delivery costs for "niche appeal" units in entertainment but not education. Technology has an equal effect on pricing for all entertainment products regardless of bestseller status; the same is not so of educational offerings, which are inherently more specialized and expensive. This cost imbalance occurs since we are less likely to move high-end, low-demand educational offerings to an automated or virtual delivery mode-precisely because they are higher-end, requiring more intensive instruction.
Even if we did recreate them for virtual delivery, it would be at great cost. This suggests that a potential for profitable Long Tails may be unlikely in highly specialized university-level courses. But if current trends are any indication, this difference could have a limited lifespan. Three factors could create a Long Tail for course offerings:
- Incremental growth in online specialized courses. Important examples: Skidmore College's University Without Walls,  the University of Pennsylvania's PennAdvance,  or Stanford University's Center for Professional Development. 
- Growing demand for higher education beyond undergraduate and professional education. This factor is seen in the great success of continuing education programs, reflecting demand for degree and non-degree programs alike.
- Continued and diverse attempts to improve the quality and delivery of higher education online, by traditional, non-traditional, and commercial institutions.
Even if these factors intensify, many challenges lie in the way of a Long Tail market. No one has set a standard for a salable unit of online education -- entire courses, elements of course materials, or something else altogether? Should those units even be sold per se? Some approaches to these issues include: Open access to self-contained courses (Carnegie Mellon's Open Learning Initiative  ); open access to curricular materials organized by courses (MIT's OpenCourseWare ); open access to curricular materials organized into course modules (Rice University's Connexions  ); continuing education courses for sale (the AllLearn  project of Yale, Stanford, and Oxford); and program courses for sale (the eCornell  project).
What really distinguishes high and low enrollment courses? Does the distinction simply consist of enrollment size? Advocates of small-sized, traditional classes argue that a highly specialized course requires an intensively personal approach that even a maximally "high touch" online learning experience cannot provide.
Even if these challenges are met, it's far from clear that traditional colleges and universities would willingly help bring about a Long Tail online market in higher education. From educational and economic perspectives, the outcome would not necessarily be positive. In literature or music sales, rescuing the backlist means exposing new audiences to unknown or forgotten worlds. By contrast, online delivery of higher education's "backlist" might well hasten consolidation of the market. How many different courses on Beowulf or Mallarmé can attain even tiny market share? With a drastic focusing of such "sales," the market could consolidate around colleges offering the best specialized courses, spelling an unhappy fate for institutions unable to compete.
Still, the potential for a Long Tail lies dormant in courses that are not yet offered online but can be found at 2,400 U.S. institutions. Year after year, a wealth of such courses, in highly focused topics such as Tagalog, Random Matrix Theory, and African traditional religion, appear in scores of college catalogues. This indicates a clear and widespread interest among current students in courses on diverse, super-specialized, arcane subject matter. There is no telling what the potential is for additional audiences of adult and returning students.
The 80-20 rule, then, is not a fixed picture, if it holds at all. The backlist 80 percent of courses represent an enormous number of classroom seats in their current, traditional mode of course delivery-and possibly many more virtual seats, if the transition is ever successfully made to online delivery. We're not likely to capture 80 percent of classroom seats by putting online 20 percent of all courses (this was obvious anyway, given that most courses taken by undergraduates are not giant lecture courses). Efficiencies may be gained by concentrating on putting large enrollment courses online. But we must be sober about the extent of those efficiencies-and about what is left out when online offerings neglect the backlist.
Is it really possible to deliver highly specialized courses online at the same levels of quality as traditional formats? Perhaps -- competent online courses or materials abound for focused topics ranging from Akkadian to causal reasoning to the history of the Jazz Age. But in case it is too costly to build those assets, colleges should look at what they are getting from ostensibly low-cost online versions of popular courses-the vaunted 20 percent. Should they demand more than "satisfactory" and "efficient" as grades of quality in those online courses-and would meeting those greater demands cost more?
Although in principle an "add sales" approach based on a Long Tail may beat a "cut costs" approach, low enrollment courses are not being created for online delivery in great numbers -- a notable exception being at MIT, where course materials alone are being digitized. As long as costs and quality remain perceived barriers to digitizing highly specialized courses, a Long Tail scenario in higher education may be a ways off. But it's worth contemplating how such a scenario might arise, and what it might mean for distributors and students ("consumers") of university-level courses. A Long Tail in niche-interest courses could build revenue opportunities for colleges and universities, consolidate markets among institutions offering such courses, and transform how students choose among courses and programs.
Saul Fisher is director of fellowship programs at the American Council of Learned Societies. He is formerly a program officer at the Andrew W. Mellon Foundation, where he directed the Teaching and Technology Program.