How do scientists learn about science and keep up with advancements in their discipline? One way is the scientific literature. Once upon a time (cue: eye roll), scientists, from students to lab directors, either went to the library or had personal subscriptions to scientific journals. At the university where I earned a Ph.D., our building housed a branch of the main library called the Chem-Math library. New graduate students were issued a key to the library, along with other keys for laboratories, classrooms, and offices. At any time of the day or night, students and faculty could be found perusing the latest issue of Analytical Chemistry or Tetrahedron Letters. In fact, one of the questions on a comprehensive exam was, "What is the color of the cover of the journal Electrochimica Acta?" (The fact that I can remember this question many years later suggests that I might have been traumatized by not knowing the answer.)
Each year the new issues of each journal were dutifully packed up and sent to the bindery to be bound into gigantic volumes. The volumes were shelved in great, colorful rows. When too many linear feet were occupied by, say, the Journal of Organic Chemistry, the older volumes were subjugated to the two sub-floors of the library. It was only a little bit scary to have to search for an article from 1923 on the lowest floor of the basement. Once you found your article, you were obligated to lug the volume to a very loud copy machine that accepted nickels and produced warm copies that were fuzzy with toner particles.
Faculty members and students also routinely checked out books. The practice was more like a medium- or long-term loan, since fines were rarely levied and books were known to pile up on faculty members' windowsills and desks for months or years. Graduate students were held to slightly more rigorous standards, although I think a book could be checked out for a semester.
Today all this can be accomplished at your desk. (Is it any wonder that we are increasing in girth and less fit?) Academic libraries still order and shelve new books, although libraries associated with industrial laboratories have largely disappeared. And scientific journals are in a great state of transition. To cut costs associated with printing and mailing, most publishers are offering personal and institutional electronic subscriptions only, with a surcharge for the paper copy, if one is still available. The American Chemical Society (ACS) publishes a large number of journals in chemistry and related fields. Once articles have been accepted to ACS journals, they are prepped for both online and print publication. Even though the actual journal issues are still released on a weekly, monthly, or bimonthly schedule, individual articles are published online as "Articles ASAP (As Soon As Publishable)." You can even sign up to get RSS alerts from your favorite journal, either through a personal or institutional subscription. Searchable subscription databases also simplify the hard work that students and researchers used to have to do in the actual library.
So while we have gained the ability to target and obtain information quickly, what have we lost? Perhaps your research advisor sent you to the library to learn about new methods in ion chromatography. While you were looking up articles on your topic, you may have come across an interesting but tangential article, or even an article on a completely different topic that may have been of use to you in some other, unknown way. I suppose serendipity can strike today if you glance at the table of contents of your online journal, but I daresay that most of us are more likely to only read what we are assigned or are interested in.
But there is a modern solution to this lack of breadth. Science journalists are big users of social media, especially Twitter. Many professors and professionals are unaware of the value of Twitter, with its seemingly silly name, in keeping up with what's new in science. Twitter has been described as a river of information. Just as the Nile River is unlike the Colorado River in content, your Twitter feed is completely customizable. And like a river, you can choose when and where to dip your toe in. You don't have to (and can't possibly) read everything. But when you have a few minutes, you can check your Twitter feed and learn about a recent discovery, publication, blog, opinion piece, or the goings on at your favorite scientific society meeting. Electronic serendipity ensues.