For popular publications, it seems clear that authors and artists will insist upon a remuneration process along traditional lines. Steven King will not offer his latest thriller for Internet access for free access and redistribution.  Madonna will not set up a World-Wide Web server providing free access to her new multimedia album.  Authors and artists expect remuneration for their creative efforts.
Over time there will be more and more demand for support for individualized document orders on demand. This would in fact make it possible for a reader (or listener or viewer, as the case may be) to request a document -- whether scholarly or popular -- for Internet delivery, with payment going to the publisher and the author or performer. The Internet Engineering Task Force has several working groups that have discussed such mechanisms. The concept calls for an "Internet 900 number" that would allow readers to select documents for which a fee is charged, with billing to take place back to an account associated with the user.
As for the scholarly journal publication process, already some university presses, scholars, and librarians are asking whether this is a role for the commercial publisher in the electronic world. Prices of scholarly journals have risen dramatically in recent years; many libraries have seen double digit price increases for several years running. The question arises: what is the role served by commercial publishers in scholarly communication? Dr. John Franks observes "Not surprisingly it has occurred to some that the main thing required to turn a preprint data base into a true journal is a volunteer editor."  Many scholars feel that the rewards of scholarly publishing lie in areas such as pride in communicating new ideas to peers, promotion and tenure, etc. Financial rewards for scholarly writing, at least in journals, are seldom substantial. Internet-mediated delivery of e- journals could liberate scholars and their institutions from the commercial aspects of the publishing process -- and could pose a serious threat to the revenue stream of commercial journal publishers.
Clearly, however, publishers of reference works and electronic books will be able to demand compensation for their investment. Anyone who has ever used a library for a research project knows that the credence one gives to a given source of information depends on the reputation of that source; individuals and libraries will pay for quality information. Whether information is to be delivered under campus licenses or individualized subscriptions, the Internet and its technologies are likely to be important in the emerging world of electronic publishing. The Encyclopedia Britannica has announced plans to make available an online edition; the initial market will be universities, and the browsing tools will be Mosaic and WAIS. Given the framework WAIS provides for charging for information, endeavors such as this may lead to a realization of a practical information-on-demand service in the Internet context. Even after pay-per-view technology is in place, it is likely that many libraries and other organizations will continue to opt for campus or site licenses as an economical alternative.
Already some entrepreneurs are working on such schemes. A company called SoftLock Services offers a scheme whereby a user can unlock software (programs or data) on demand. The user or reader contacts SoftLock via telephone, dial-up, e-mail, or fax, provides credit card or other payment information, and receives a key in return.  Given an Internet authorization and accounting infrastructure, client programs such as Mosaic could perform such transactions on the user's behalf.
A related problem to the question of ensuring compensation for use of intellectual property is the question of verifying that an electronic document is in fact unaltered from the form in which it was originally published. It is trivial to use an editor to alter a file fetched over the Internet; an unscrupulous archivist  could post the altered file with no notification and with the original author and title.
One solution to this problem will be multiple document archives at trusted locations. Libraries may take on this role. If more than one trusted archive shows the same version of a document, readers will have confidence of its authenticity.
Here, too, software can be brought to bear on the problem. Public key encryption is one possible answer; an author can trust that a reader has a valid copy of a document because only the author is able to create that exact sequence of text. Another scheme, known as "hashing," performs a mathematical operation on each of the characters within a document, the result of which is a "hash" to be carried with the document and all online references to the document. Software can to calculate the hash for a purported copy of the document, and compare the hash with the separately- published value; if the hashes are identical, the document is authentic. 
Certainly, that model will be implemented. But it is not the only model for a virtual library, and it misses a subtler, but vastly more important, connotation of the word "virtual." For years the concept of "virtual memory" has a part of the computing lexicon. Simply put, virtual memory allows the user of a computer to pretend the machine has far more memory than is physically installed. This is accomplished by dedicating some of the machine's disk space to the task of extending the bank of apparently-installed memory. The concept was first deployed in the late 1960s on mainframes, and made its way over time to minicomputers and now to personal computers. Your 80486 PC running MS-Windows, or your Macintosh running System 7, exploit virtual memory.
It is in this sense -- the idea of extending a resource beyond what is physically installed -- that the virtual library concept is most compelling. The traditional library invests a huge amount of capital, in the form of physical shelf space and budget for acquisitions, in order to meet the needs of its patrons. At any given instant, however, only a tiny fraction of the materials in a library is in use. The vast majority of books and space are, in a sense lying fallow. When the next reader walks in and finds the book or journal that happens to meet a personal need, that particular item suddenly becomes valuable.
Not only do some items remain on the shelf, never to be used; the opposite situation also occurs frequently: two or more readers want access to a particular item, and that item is checked out by another patron. This is such a natural part of using a library that we are all quite accustomed to the process: We search the catalog, and find what appears to be exactly the right book, but alas it is not on the shelf.
The traditional library has ways of dealing with the problem of highly-desired items being in use. First, libraries limit the length of time an individual can use a particular item. Some libraries also institute a "recall" process whereby the patron currently holding an item desired by another patron is asked to return it. Libraries may also have a policy of trying to order additional copies of items that are particularly popular. Finally, libraries may have an interlibrary loan agreement with peer institutions. Through interlibrary loan, a reader can not only obtain an item when the local copy is in use; the reader may be able to gain access to a book or journal article that the local library never acquired in the first place. (When copies of journal articles are made under such arrangements, provisions are made to provide compenstaion to the holders of copyright.)
The virtual library concept exploits the instant reproducibility of electronic materials to extend the scope of any given library's collection. It is not necessary for the local library to have all items that patrons might desire physically in its inventory. Instead, the library can electronically obtain a copy of the item at the time the patron needs it. The Japanese automotive industry pioneered a method of cost savings called "just-in-time" inventory control: parts are delivered to factories as needed, eliminating the need for costly stockpiles. In the library community, this concept is expressed as "just-in-time instead of just-in-case." It is a fundamental shift in the way a library fulfills its mission.
Inventor and author Raymond Kurzweil has lectured and written on this transition. He has identified two major advances in the delivery of large electronic documents -- electronic books -- that must take place before the virtual library model can develop:
This process works extremely well for transmission of relatively small amounts of information. For larger works, such as books, no reader would want to cope with hundreds of pages of loose paper for serious reading. One can envision technology that might provide on-site printing and binding of large volume materials, which may prove to be a viable alternative.
Another alternative to physical printing would be online display. Despite advances in display technology, the very best monitors, costing thousands of dollars, still do not approach the quality of the printed page. High-quality printing on high-quality paper has resolution and contrast characteristics unmatched by computer monitors. Moreoever, high-resolution documents take a tremendous amount of disk space, and require high-end processing power to support rapid scrolling and paging.
Visionaries like Kurzweil see the inevitable march of technology providing answers to these problems. Magnetic and optical disk technologies continue to advance rapidly, in terms of miniaturization, capacity, and cost. Display technology, such as active matrix liquid crystal displays, will offer higher resolution and lower power requirements. Processor power has been on a path of incredible improvement for many years: a given investment buys twice as much computing power as the same investment would have bought a year to 18 months earlier. Battery technology continues to improve.
This line of thinking argues that we will see notebook computers with sufficient computing power, display quality, storage capacity, and battery life to serve as a viable replacement to the printed book within a few years. At that time the electronic distribution component of the virtual library can become a reality.
The issue of compensation of authors for their creative efforts becomes even more important in an environment where an entire book can be downloaded to a hand-held digital display device, and when that technology becomes an accepted alternative to reading traditional bound paper books. The techniques for protection of documents discussed earlier must mature in order before authors will relinquish their works for distribution via the virtual library. When those technologies are in place, and when acceptable global catalogs are in place, libraries can cease the practice of ordering books for their inventory. Instead, when a patron wishes to obtain a particular title, an online order can be processed at the time of "check out."
Some skeptics wonder how this model leaves any room for the library at all. If the library has to pay for each use of the book, how can public library budgets afford to support free individual check-out of books? Advocates of virtual libraries reply that in a pay-per-view world, the price of a title can be set far lower than in today's market, when the publisher hopes to recover value in proportion to the level of usage enjoyed by the institution. They argue that the just-in-time, virtual delivery model could actually stretch library book and periodical budgets to include access to far more titles; moreover, the titles acquired will be precisely those that patrons demand. Advocates argue that the digital future can even accommodate a form of online browsing at no charge, whereby the reader can skim a virtual copy and decide whether to acquire the particular item.
Those who love books may find the concept of a virtual library discomforting. No virtual library can offer the pleasure of browsing the stacks or of leafing through a book with handsome typefaces and superior paper and bindings. Even when portable display technology and intellectual property protection issues are resolved, will that be the death knell of books and magazines? This is not easy to predict, but few are claiming that printed materials will disappear within the next few decades.
In the near future, we can expect to see a range of archive alternatives for Internet information publishers. These might include:
Already the term "Virtual Library" has been adopted by some Internet information providers. In one sense, these nascent efforts could be seen as simple subject catalogs. In fact, they do meet the essential aspect of a virtual library -- they offer a set of documents that are not physically located on their server, but rather are located anywhere on the global Internet. Some of the earliest virtual libraries include the Library of Congress' Marvel service, and North Carolina State University's Library without Walls