By BENNY EVANGELISTA, San Francisco Chronicle

When the first Segway rolled out in public for the first time 10 years ago, the tech world was disappointed to see it was just a two-wheeled "human transporter."

SAN FRANCISCO - The Twitter stream, which last month proved to be a vital link for anti-government protesters in the Middle East, quickly turned into a worldwide forum for comfort, heartbreak and hope for Japan's quake-stricken residents.

Social-networking powerhouses Twitter and Facebook once again became important communications tools in a natural disaster.

SAN FRANCISCO - Twitter Inc. gained more than 100 million registered members this year and approaches the New Year with a fresh investment of $200 million.

Now it must prove it can live up to its newly elevated valuation of $3.7 billion.

SAN FRANCISCO - Since the dawn of the Internet age, basic e-mail has remained the online world's version of comfort food -- familiar and unchanging.

But the rapid rise of other forms of electronic communication are transforming e-mail from a stand-alone application into one that incorporates mobile text, chat, instant messaging, Facebook, Twitter and online document sharing.

Social networking should reduce friction between humans around the world by 2020, but the technology could also rob people of face-to-face relationships and foster shallower relationships, according to a new survey of top tech leaders and experts.

For the magazine industry, Apple's iPad isn't just a new gadget -- it's an opportunity to get readers to do what they have been reluctant to do: Pay for digital content.

Magazines ranging from Wired, born in the digital age, to National Geographic, first published in 1888, are moving aggressively to reinvent themselves for the iPad and other tablet computers coming to market.

Research scientists Cameron Marlow and D.J. Patil have unprecedented windows into the social interactions of people around the world.

Marlow is manager of a data-science team for Facebook Inc., which has more than 400 million members who come to socialize online.

Launched only two months ago, CauseWorld is already raising about $200,000 per month for various community organizations with a mix of mobile phone applications, geo-location technology and social media.

Meanwhile, BetterWorldBooks uses Facebook and Twitter to publicize book drives that fund about 80 literacy programs that help schools, libraries and other nonprofit organizations.

On March 15, 1985, a Massachusetts computer-systems firm registered the first ".com" Internet domain name.

Although Symbolics.com didn't spark an instant gold rush, the event planted the first seed of a transformation that has changed the world into a Web-fueled digital river of news, commerce and social interaction.

The Internet, especially in the era of Facebook, Twitter and smart phones, is transforming the way Americans consume their daily news into a "shared social experience," according to a report released Monday.