Twitter said Wednesday that it is adding a photo-sharing option for its users, a move that could deal a blow to existing services such as Twitpic and yfrog.

Twitter chief executive Dick Costolo also announced at the All Things Digital technology conference here that the San Francisco-based service was upgrading its search function.

Two young men and two women were found dead in a car Thursday in an apparent Internet-based group suicide, South Korean police said.

Police said the four, including a 25-year-old woman identified only as Park, left suicide notes in their bags in the car parked next to a river in Seongju, 210 kilometers (126 miles) southeast of Seoul.

Making online friends could play into the hands of the "enemy", according to China's People's Liberation Army, which has said its roughly 2.3 million soldiers will be banned from using social media.

The world's largest military force has notified servicemen and women that it will strictly enforce the ban to "safeguard military secrets and the purity and solidarity" of the PLA, state media said this week.

Twitter on Tuesday broadened its reach by letting websites add "Follow" buttons that visitors can click to begin tracking posts at the globally popular microblogging service.

Twitter billed the button as "a new way to follow Twitter accounts directly from the websites you visit every day."

Ailing chief executive Steve Jobs returns next week from sick leave to unveil Apple's latest generation of software, the firm announced Tuesday.

The 56-year-old cancer survivor will present Apple's new operating system, dubbed "Lion," at a developers' conference in San Francisco on June 6.

Activision knows it's more fun to blast on-screen enemies into oblivion with friends, so this fall it's launching an online service for its "Call of Duty" games that's part Facebook, part player matchmaker and part organized sports.

It's the logical next step for Activision Blizzard Inc., whose "Call of Duty" franchise has enjoyed unprecedented success. The latest title, "Black Ops," has sold 22 million copies worldwide since its November launch. More than 7 million people play every day online.

Samsung Electronics will depend on Google's Android mobile-device software to run future versions of its tablet computers, a senior Samsung official said in an interview published Tuesday.

"We'll continue to work with Android on future tablets," J.K. Shin, head of the South Korean giant's mobile division, told The Wall Street Journal.

Young people's fascination with television, the Internet, video games and other electronic entertainment is making it more difficult to protect the world's biodiversity, a U.N. official warned Tuesday.

Because many young people are urbanized and alienated from nature, they may not realize the value of protecting natural ecosystems and species, said Ahmed Djoghlaf, the United Nations executive secretary on biological diversity.

Instead of paying attention in high school, Nick Cammarata preferred to read books on whatever interested him. He also has a gift for coding that got him into Carnegie Mellon University's esteemed computer science program despite his grades.

But the 18-year-old programmer won't be going to college this fall. Or maybe ever.

Computer manufacturers of all sizes and descriptions have been pushing to get a piece of the ever-expanding tablet market created by the launch of Apple's iPad in April 2010.

The obsession with tablet computing will be on full display Tuesday as Computex, the world's second-largest computer show, begins its annual five-day run in Taipei. The prominence of tablets underscores a dramatic shift under way in the personal computer industry — and keenly felt in Taiwan, which is home to some of the world's biggest PC manufacturers — as many consumers opt to buy a tablet rather than a new PC.