Sheryl Sandburg had a bombshell announcement for technology experts this week: "I hate to be the bearer of bad news... but e-mail is probably going away." The key to figuring out how the rest of us will communicate tomorrow, Sandburg told the audience at Nielsen's Consumer 360 conference, is looking at "what teenagers are doing today," and teens overwhelmingly use texting and social networks to keep in touch. What they don't do is email — only 11 percent of teens use it daily. "She's almost certainly on the right track," says Derek Thompson at The Atlantic. Technology changes at such a breakneck pace that something new will almost certainly "eclipse" email within a few years. Come on, email's still "the killer app," says Maggie Shiels at BBC's Silicon Valley blog. It's nowhere near "its sell-by date," even if 90 percent of it is spam or some other kind of "useless twaddle." Watch Sandburg's email speech — complete with several more predictions about how Facebook might shape society — here: