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The U.S. government has used the merger-approval process to increase its influence over the telecom industry, bringing more companies under its oversight and gaining a say over activities as fundamental as equipment purchases.

The leverage has come from a series of increasingly restrictive security agreements between telecom companies and national-security agencies that are designed to head off threats to strategically significant networks and maintain the government's ability to monitor communications, according to a review of the public documents and lawyers who have negotiated the agreements.

Amazon.com is taking a fight over sales tax in the state of New York to the U.S. Supreme Court. Exactly why is a little unclear.

The online retailer on Friday filed documents to appeal the issue to the nation's highest court, arguing that Amazon customers shouldn't be subject to sales tax in New York because the Seattle company's operations there aren't substantial enough to trigger the levies.

The co-founder and technical guru behind Yandex NV, Russia's largest Internet search engine, is in a coma with no signs of brain activity, the company's chief executive said Thursday.

Ilya Segalovich, who has been battling cancer, is on life support, CEO Arkady Volozh said on a conference call. Earlier Thursday, Yandex announced that Mr. Segalovich, 48 years old, had died.

"Last night, the family of Ilya [Segalovich] announced that he died. In the morning, the information came through that Ilya is hooked up to life support. We are awaiting official information and for now are abstaining from comments," the company's spokesman said in an emailed comment following the call.

Tesla Motors Inc. CEO Elon Musk offered a detailed explanation Friday afternoon of why a Model S caught on fire this week and tried to squelch safety concerns that weighed on the stock price.

"For consumers concerned about fire risk, there should be absolutely zero doubt that it is safer to power a car with a battery than a large tank of highly flammable liquid," Mr. Musk wrote in a blog post on the company's Web site.

The Obama administration official directly responsible for the botched rollout of the federal health-insurance website apologized Tuesday at a congressional hearing, saying the site "can and will be fixed."

Marilyn Tavenner, administrator of the Centers for Medicare & Medicaid Services, apologized to millions of Americans who have unsuccessfully tried to access the site and shop for insurance. "The website hasn't worked as well as it should," Tavenner said.

The National Highway Traffic Safety Administration said it would launch a formal investigation into recent fires that destroyed two Tesla Motors Inc. Model S electric cars that had run over metal debris.

"The agency's investigation was prompted by recent incidents in Washington state and Tennessee that resulted in battery fires due to undercarriage strikes with roadway debris," the agency said in a statement. The probe would determine whether the vehicle has a defect that makes it dangerous and could result in a recall and remedy.

The nation's phone system is changing quickly and it is time for the regulators to catch up, new Federal Communications Commission Chairman Tom Wheeler said Tuesday.

Mr. Wheeler, in a blog post, outlined his plan to move forward with what has become known as the IP Transition, the shifting of landlines from circuit-switched systems to a digital, Internet Protocol-based network. Mr. Wheeler said he expects the FCC to vote in January to begin collecting data and conducting trials, in hopes of figuring out how existing regulations must be tweaked to suit an all-digital communications network.