(FORTUNE Small Business) – They were a scholar, a drunk, and a clown, with a plan to tap the Scottish Enlightenment for all it was worth. As it turned out, putting all of 18th-century culture into serialized book form didn't make the threesome rich or famous. But their creation, the Encyclopaedia Britannica, has outlived any reference work in the English language. And the way it turned information into a powerful brand could be an inspiration for the 21st-century contentmeisters.

For many American readers, Britannica conjures up images of a salesman at the door playing on Mom and Dad's guilt ("You want your kids to go to college, right?"), the leatherette volumes lending gravity to living room shelves, or the all-nighter for a report on the Panama Canal. Britannica was synonymous with encyclopedia.

Even in 1768, encyclopedias weren't new. Compilations on art and science go back before the time of Christ, and Diderot's Encyclopedie inspired Britannica's founders. But they had a twist: Make the work useful to the growing masses of literate people--and make money doing it.

The Britannica dream team included Colin Macfarquhar, a printer and bookseller; William Smellie, a 28-year-old editor and imbiber of whiskey; and Andrew Bell, an eccentric engraver who stood four-and-a-half feet tall and had a big nose and a sense of humor. (He liked to wear an even bigger papier-mache nose.) They were residents of Edinburgh, a mecca for writers and philosophers whose focus was veering away from the church and to natural sciences. Britannica's editors wanted to capture the zeitgeist of the Enlightenment, and their choices are telling. Drama was allotted seven lines, poetry got 500 words, and farriery (cures for horse diseases) 39 pages. The first edition, in weekly installments, sold out; 3,000 people bought them, then took them to cobblers to bind. The book was soon a global phenomenon. Bibliophiles such as Thomas Jefferson and George Washington snagged pirated versions. But it wasn't until Sears Roebuck bought Britannica in the 1920s that it blossomed into a real commercial enterprise. An aggressive sales force and a tweedy editorial staff was a potent combination. And Britannica stayed ahead of new, middlebrow competitors like World Book.

But the very concept of "encyclopedic" knowledge was becoming antiquated. Information may be the currency of the age, but when it increases at warp speed, a static summary becomes impossible. "It's a quaint remnant of a time that simply doesn't exist anymore," says Syracuse University's media guru, Robert Thompson.

By the early 1990s encyclopedia sales were sliding, and Britannica, which had changed hands several times, was way behind the likes of Microsoft, with its $99 Encarta encyclopedia. (It might not have the scholarly heft, but Encarta does things print can't. Touch a picture of Titian's "Worship of Venus," and it pronounces the painter's name: "Tish-en.") Five years ago, Britannica was kicked into higher gear by a new owner, financier Jacob E. Safra, who started by sacking the sales fleet. (Yes, you can still buy it.) Britannica.com, though, launched in 1999, is another kind of entry point for knowledge: a portal. Updated daily and decked out with weather reports and ads, it is no literary achievement. But it probably reflects our zeitgeist--what some consider a new Enlightenment.