South Korea's Samsung Electronics on Thursday unveiled its latest flagship smartphone at a London launch as it seeks to cement its position as the world's best-selling mobile phone maker.

The Galaxy S3 boasts a 4.8-inch screen (12.2cm), 22 percent larger than the Galaxy S2, the hugely popular predecessor that helped the company overhaul Nokia as the world leader.

In a flashy presentation to advertisers, YouTube promoted its new channels of original programming, while pledging to spend $200 million to help market them.

That's roughly twice what the Google Inc.-owned video site has spent launching some 100 channels of niche-oriented programming. The channels are an ambitious initiative from YouTube, approximately halfway through its rollout.

Nokia, one of the world's leading mobile phone makers, said Wednesday it had filed patent infringement lawsuits against mobile phone and electronics groups HTC, RIM and ViewSonic in the United States and Germany.

"Though we'd prefer to avoid litigation, Nokia had to file these actions to end the unauthorized use of our proprietary innovations and technologies, which have not been widely licensed," Nokia said in a statement.

Research in Motion Ltd. says future BlackBerry models will still offer physical keyboards.

Some reports suggested RIM would ditch the physical keys favored by its users, but CEO Thorsten Heins said Wednesday that RIM won't lose the focus on physical keypads.

Web wanderers are more likely to get a computer virus by visiting a religious website than by peering at porn, according to a study released on Tuesday.

"Drive-by attacks" in which hackers booby-trap legitimate websites with malicious code continue to be a bane, the U.S.-based anti-virus vendor Symantec said in its Internet Security Threat Report.

A virus infecting Macintosh computers is picking Google's pocket by hijacking advertising "clicks," tallying as much as $10,000 daily, according to Internet security firm Symantec.

A component of the widespread Flashback virus targets Google search queries made using Chrome, Safari, or Firefox browsers and directs people to pages dictated by the hackers, Symantec said Tuesday in a blog post.

Facebook is on track to make its historic multi-billion-dollar debut on Wall Street on May 18, The Wall Street Journal reported on Tuesday.

Executives from the social network plan to begin a financial roadshow next week, going to various cities to discuss Facebook's prospects with potential investors before the initial public offering, the newspaper said.

Ugly meter is an iPhone app that rates how ugly you are, has attracted millions of users going up the chart, according to the UK Daily Mail.

The application takes your picture and scans the contours of your face before rating you on a scale of 1 to 10, knowing its least favored for people to score a perfect 10 in this game.

PepsiCo Inc. is tweeting to a new generation of music lovers.

The No. 2 soda company said Monday that it's partnering with Twitter to provide streaming videos of live music concerts to Pepsi's followers on the social networking site. The deal is part of Pepsi's new global ad campaign that will also feature a TV ad with singer Nicki Minaj.

Travelers who suspect they are victims of profiling by security screeners at U.S. airports can now lodge a complaint in minutes, thanks to a smartphone application released on Monday.

The Sikh Coalition, supported by African American, Latino and Muslim civil rights groups, said its FlyRights app can be used by anyone who feels their rights were violated at the security barrier.