University of Chicago sociologist James Evans reports on a massive study that suggests that, as scientists use more online resources, their reading habits change– resulting not in more interdisciplinary work that ignores traditional textual and institutional boundaries (the situation imagined by early hypertext reading advocates like George Landow), but rather (as the abstract put it) a "narrowing of science and scholarship:"

Online journals promise to serve more information to more dispersed audiences and are more efficiently searched and recalled. But because they are used differently than print—scientists and scholars tend to search electronically and follow hyperlinks rather than browse or peruse—electronically available journals may portend an ironic change for science. Using a database of 34 million articles, their citations (1945 to 2005), and online availability (1998 to 2005), I show that as more journal issues came online, the articles referenced tended to be more recent, fewer journals and articles were cited, and more of those citations were to fewer journals and articles. The forced browsing of print archives may have stretched scientists and scholars to anchor findings deeply into past and present scholarship. Searching online is more efficient and following hyperlinks quickly puts researchers in touch with prevailing opinion, but this may accelerate consensus and narrow the range of findings and ideas built upon.

The full article has some fairly complicated statistics and methodological explanations, but these couple paragraphs describing how reading and citation patterns have changed are especially striking:

[A]s journal archives came online, either through commercial vendors or freely, citation patterns shifted. As deeper backfiles became available, more recent articles were referenced; as more articles became available, fewer were cited and citations became more concentrated within fewer articles. These changes likely mean that the shift from browsing in print to searching online facilitates avoidance of older and less relevant literature. Moreover, hyperlinking through an online archive puts experts in touch with consensus about what is the most important prior work—what work is broadly discussed and referenced. With both strategies, experts online bypass many of the marginally related articles that print researchers skim. If online researchers can more easily find prevailing opinion, they are more likely to follow it, leading to more citations referencing fewer articles. Research on the extreme inequality of Internet hyperlinks, scientific citations, and other forms of "preferential attachment" suggests that near-random differences in quality amplify when agents become aware of each other's choices. Agents view others' choices as relevant information—a signal of quality—and factor them into their own reading and citation selections. By enabling scientists to quickly reach and converge with prevailing opinion, electronic journals hasten scientific consensus. But haste may cost more than the subscription to an online archive: Findings and ideas that do not become consensus quickly will be forgotten quickly. This research ironically intimates that one of the chief values of print library research is poor indexing. Poor indexing—indexing by titles and authors, primarily within core journals—likely had unintended consequences that assisted the integration of science and scholarship. By drawing researchers through unrelated articles, print browsing and perusal may have facilitated broader comparisons and led researchers into the past. Modern graduate education parallels this shift in publication—shorter in years, more specialized in scope, culminating less frequently in a true dissertation than an album of articles.