A report released last year by the National Federation of the Blind, an advocacy group with 50,000 members, said that less than 10 percent of the 1.3 million legally blind Americans read Braille. Whereas roughly half of all blind children learned Braille in the 1950s, today that number is as low as 1 in 10, according to the report. The figures are controversial because there is debate about when a child with residual vision has "too much sight" for Braille and because the causes of blindness have changed over the decades -- in recent years more blind children have multiple disabilities, because of premature births. It is clear, though, that Braille literacy has been waning for some time, even among the most intellectually capable, and the report has inspired a fervent movement to change the way blind people read. "What we're finding are students who are very smart, very verbally able -- and illiterate," Jim Marks, a board member for the past five years of the Association on Higher Education and Disability, told me. "We stopped teaching our nation's blind children how to read and write. We put a tape player, then a computer, on their desks. Now their writing is phonetic and butchered. They never got to learn the beauty and shape and structure of language."

For much of the past century, blind children attended residential institutions where they learned to read by touching the words. Today, visually impaired children can be well versed in literature without knowing how to read; computer-screen-reading software will even break down each word and read the individual letters aloud. Literacy has become much harder to define, even for educators.

"If all you have in the world is what you hear people say, then your mind is limited," Darrell Shandrow, who runs a blog called Blind Access Journal, told me. "You need written symbols to organize your mind. If you can't feel or see the word, what does it mean? The substance is gone." Like many Braille readers, Shandrow says that new computers, which form a single line of Braille cells at a time, will revive the code of bumps, but these devices are still extremely costly and not yet widely used. Shandrow views the decline in Braille literacy as a sign of regression, not progress: "This is like going back to the 1400s, before Gutenberg's printing press came on the scene," he said. "Only the scholars and monks knew how to read and write. And then there were the illiterate masses, the peasants."

Is there gold in them thar tweets?

Maybe so, because-according to sources familiar with the situation-Twitter is in advanced talks with Microsoft and Google separately about striking data-mining deals, in which the companies would license a full feed from the microblogging service that could then be integrated into the results of their competing search engines.

Sources said a number of scenarios are being discussed to compensate Twitter for its huge and potentially valuable trove of real-time and content-sharing information, generated from the data stream of billions of tweets from its 54 million monthly users.