I was working at the University of California in the early 1980's when the UC union catalog, MELVYL, was developed. Shortly after MELVYL became available as one of the early online public access catalogs, we obtained a copy of NLM's Medline database, consisting of articles and books in a wide variety of fields related to medicine. This was the first article database that we were making available. At that time, the only people who had access to Medline were medical researchers in the four or five medical centers at the university, and they accessed it via the Dialog search service. Dialog charged by the minute and was relatively pricey. Few members of the university community had access to Dialog's databases in any subject area because of the cost.
I don't know how many minutes or hours of searching were done monthly on Medline before we added the database to the university's library system, but within a few years the number of searches on Medline were rivaling the number of searches in the entire union catalog of the 9 university campuses. It was heavily used even on those campuses that had no medical school. Had everyone developed a sudden interest in the bio-medical sciences? Perhaps, but not to that degree. I think that we had created a monster of "availability." As the only freely available online database of articles, Medline became the one everyone searched.
(If anyone is looking for a master's thesis, try looking at the citations in dissertations granted at the University of California for the period 1985-1995, and compare it to the previous decade. Count how many of the cited articles come from journals that are indexed in NLM's database. I have a feeling that it will be possible to see the "Medline-ization" of the knowledge produced by that generation of scholars, from architecture to zoology. )
When we make materials available, or when we make them more available than they have been in the past, we aren't just providing more service -- we are actually changing what knowledge will be created. We tend to pay attention to what we are making available, but not to think about how differing availability affects the work of our users. We are very aware that many of us are searching online and not looking beyond the first two screens, which produces an idiosyncratic view of the information universe. But we don't see when libraries create a similar situation by making certain materials more available than others (for example scanning all of their out-of-copyright works and making them available freely as digital texts, while the in-copyright books remain on the shelves of the library).
There's a discussion going on at the NGC4LIB list about the meaning of "collection." What is a library collection today? Is it just what the library owns? Is it what the library owns and also what it licenses? Does it include some carefully selected Internet resources? Some have offered that the collection is whatever the library users can access through the library's interface. I am beginning to think that access is a tricky concept and it is inevitably tied up with the realities of a library collection. Users will view the library's collection through the principle of least effort. In the user view, ease of access trumps all -- it trumps quality, it trumps collection, it trumps organization. So we can't just look at what we have -- we have to look at what the user will perceive as what we have, and that perception will necessarily be tempered by effort and attention. To our users, what the library has will be what is easiest to locate and fastest to arrive.
In other words, our collection is not a quantity of materials. The collection is a set of services built around a widely divergent set of resources. To the user, the services are the library, especially because any one user will see only a tiny portion of what the library has to offer. The actual collection -- those thousands or millions of library-owned items -- is not what the user sees. The user sees the first two screens of any search.
Hopefully, they are not in main-entry alphabetical order.