In the short time since IBM launched its pioneering PC on Aug. 12, 1981, teenagers have gone from hiding secrets in locked diaries to baring all on social networking websites such as Facebook and MySpace.
Rather than inking letters to faraway pals, people send instant messages while watching friends on Web cameras.
Computerized mobile telephones banished worry about missing calls or finding friends in crowds.
Long-distance toll calls have yielded to free chat via computers linked by the Internet.
People can search online for anything from love to medical advice or bargain airfares.
Computers have enabled the masses to make videos, books, music or films at home for global consumption. Apple Computer’s iPod music and video players have engendered a style of do-it-yourself radio called "podcasting."
Personal computers have given the world telecommuting, video games and sedentary lifestyles blamed for expanding waistlines.
Humanity’s accumulated knowledge has been migrating to the Internet for anyone to find while computers have become smaller, faster and more versatile.
"It has made a stunning diffe-rence in people’s lives," Electronic Frontier Foundation legal director Cindy Cohn said. "And we are still in the early stages of this stuff.
"We will see a big leap when wireless is ubiquitous. Things you and I couldn’t dream of," she said.
The unprecedented access to people and information provided by computers has changed society’s privacy landscape, said Cohn, whose non-profit legal group champions Internet users’ rights.
Store discount cards and rewards programs such as those offered by airlines or hotels use computers to amass data about shopping and travel preferences.
Credit cards, banks and telephone companies record user activities.
Internet firms that provide free services such as online searches, maps, and e-mail save information typed in by users and sort it by unique identification numbers in the machines.
"With so much of our lives digital, the ability of the government and other people to know what we are doing, reconstruct our lives and basically stalk us online has grown," Cohn said.
The effects of computers on society go far deeper than online lifestyles, according to Fred Turner, a Stanford University assistant professor who specializes in the intersection of media and cultural history.
"The computer brings the world into the home like the television did before it," Turner said. "But it is also a window that lets others look into your world, particularly your bosses, people you buy from or sell to, and our government."
Computers have flourished as a platform for social networking, with groups ranging from online cliques to fantasy worlds inhabited by animated custom "avatar" proxies that party, work, and buy virtual property.
The ability of anyone with a computer to quickly put video, text, or audio on the Internet unleashed a flood of weblogs and "citizen journalism" that, while democratic, lacked standards for integrity and reliability, Turner said.
The full effects that computers and the Internet will have on journalism, education and the military are yet to be known, he said.
"If the Internet corrodes the institutions our culture depends on, then we may have new social networks but lose very valuable social goods," Turner said.
"For example, digitally enabled networks can fight in a loosely organized way that highly challenges organized armies. You see that in Lebanon right now with Hezbollah and to some degree in Iraq," he added.
Computers have also given social movements new tactics such as "flash mobs," throngs that carry out orchestrated actions in a public place unified solely by the direction of digital messaging.
Flash-mob events have ranged from a pillow fight in downtown Toronto to civil unrest in France last year, according to Wikipedia, an online encyclopedia that used computers to tap into the world’s collective knowledge.
"Doing reporting and political protest simultaneously," Turner said, "that might be a new kind of social organization."
People using computers have posted video messages from embattled areas of Lebanon and US soldiers have sent messages home from Iraq in video weblogs on the website YouTube.
"Computers have given us an explosion of communication," Cohn said. "Not only between loved ones, but finding that one other person in the world who likes underwater basket weaving."