Popular Mechanics posted an article discussing the humble beginnings of classifying information using index cards and how that system foresaw the creation of the Internet.
For thousands of years, if you wanted to find the best and most comprehensive information about anything, you headed to a library. You just had to check two things first: whether the library had the information you're looking for, and, if so, where to find it. These days we can get [a lot of] this information from our computers in seconds, but as recently as the 1990s, online catalogs were new and mostly unavailable, and that meant combing through the card catalog to track down a book.
Librarians originally handwrote the bibliographies on each card. But in 1971, the Ohio College Library Center began printing the text onto the index cards for them. The OCLC distributed about 1.9 billion cards before shutting the service down in 2015—with today's online catalogs, there was little need to make more cards. The last order was placed by Concordia College in Bronxville, N.Y. as a backup to its own online catalog.
Many libraries still use the OCLC system for copy cataloging for our online catalogs. So how did the index card portend the Internet?
Long before the verb "to google," [Paul] Otlet and his friend Henri La Fontaine set out to develop their own search engine in Brussels in 1895. They wanted to create the go-to place for everyone to find information on absolutely anything. It would work just like Google does today—you submit a query and get links to relevant sources of information. In the 1895 version, you'd send queries by mail or telegraph and get index cards with bibliographies in return. The search engine service, called the Mundaneum, was a business. When you submitted a query, the bibliographies and descriptions were copied from the Mundaneum's cards onto new cards. The new cards were then sent to you, as long as you paid a fee per card.
Otlet's idea of a digitized version of information wasn't just a prediction. It was a dream. He and La Fontaine aimed to connect everyone around the world through knowledge. Had he lived until 1989—he would have 121 years old by then—he would've witnessed the invention of the World Wide Web.
And just because card catalogs are no longer necessary, it doesn't mean that libraries or librarians have lost their relevance, too. Libraries are, in fact, alive and well as they continue to transition to a digital environment and sift through the unfathomable amount of information that is created in today's world to provide reputable information to their users.