It's do-or-die time for Yahoo and Marissa Mayer.

After cutting the cord with China's Alibaba, the high-profile Yahoo chief executive faces more pressure than ever to reinvent the fading Internet star.

U.S. online giant Amazon announced plans Wednesday to offer a cloud-based email and calendar service to directly compete with Microsoft Outlook and others.

The service dubbed Amazon WorkMail "enables users to send and receive email, manage contacts, share calendars, and book resources using the same email applications they use today" including Outlook and services like Google Apps.

Samsung Electronics posted its first drop in annual net profit in three years Thursday and saw resurgent arch-rival Apple barge in on its pole position as the world's top smartphone maker.

The South Korean firm, whose key mobile phone operations have struggled in the face of intense competition from cut-price Chinese rivals, also warned that it expected 2015's "business environment... to be as challenging as 2014."

The fight against Islamic State jihadists is taking place online as well on the battlefield, with 18,000 Twitter accounts linked to the group suspended in recent months, according to a U.S. expert.

IS supporters "are under significant pressure, with the most active and viral users taking the brunt of the suspensions" J. M. Berger, a fellow at the Brookings Institution who tracks militants on social media, told lawmakers on Tuesday.

Twitter on Tuesday began rolling out new group chat and video features as it worked to ramp up use of the one-to-many messaging service.

"Private conversations on Twitter are a great complement to the largely public experience on the platform," product director Jinen Kamdar, whose handle is @jinen, said in an online post.

A U.S. government consumer watchdog agency called Tuesday for better privacy and security to be built into the myriad of connected devices, for fitness, smart homes or other uses. 

The "Internet of Things" guidelines released by the U.S. Federal Trade Commission stop short of a new regulatory effort but nonetheless provoked critics who said the agency is overstepping its authority.

Google's super-fast Internet service -- up to 100 times quicker than basic broadband -- is heading for four more U.S. metropolitan areas as the technology titan ramps up pressure on cable service giants.

A Google Fiber program launched nearly five years ago will expand to 18 cities in the Atlanta, Charlotte, Nashville and Raleigh-Durham areas.

Google's newly acquired Waze application poses a danger to police because of its ability to track their locations, the Los Angeles police chief said in a letter to the tech company's CEO.

According to the document police chief Charlie Beck sent to Google CEO Larry Page on December 30, people are using the "unwitting" Waze community as "their lookouts for the location of police officers."

Microsoft on Monday reported that its quarterly profit dipped but revenue increased in a sign that it is adapting to lifestyles centered on mobile devices and cloud services.

Bright spots during the three-month period ending December 31 included rising sales of Microsoft devices such as Surface tablets, Lumia smartphones, and Xbox One video game consoles.

Alfredo Castellano travels half an hour to Havana twice a week to write emails in a computer center with a Fidel Castro poster outside and aging machines inside.

Like most Cubans, he lacks Internet access at home, but many hope this will change after the United States offered to bolster the communist island's tightly-controlled telecommunications as part of a historic diplomatic detente.