Stuart Ramson/AP Time Warner, the world's largest media and entertainment company, is being acquired by America Online for about $166 billion in stock in what would be the biggest corporate merger ever.

By acquiring Time Warner, the world's largest media and entertainment company, AOL has leveraged itself to deliver high-speed Internet access to millions of Americans.

Monday's record $160-billion stock deal gives the world's leading Internet provider a hook to Time Warner's 13 million cable-TV customers for Net access that is up to 100 times faster than delivery through traditional phone lines.

That means far faster download times and the ability to view rich information such as movies, music and 3-D graphics. However, some groups worry that the merger of two giants also will mean fewer choices for consumers.

Known for its mass-mailings of computer diskettes for dial-up access, AOL is expected to aggressively promote its high-speed Net service through Time Warner's media outlets. While AOL is by far the largest provider of Internet access through traditional phone lines with 22 million subscribers — including its CompuServe service — its future growth is limited by uncertainty over how it would deliver its entertainment, news and services over high-speed Internet lines.

"We're still scratching the surface" of the Internet's potential, AOL chairman Steve Case told a news conference. Case will be chairman of the new company, which will be called AOL Time Warner Inc., and Time Warner chairman Gerald Levin will be its chief executive. America Online shareholders will own 55 percent of the company, and Time Warner shareholders the rest.

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Consumer and business appetite for alternate Internet access has intensified because traditional phone lines often take frustratingly long to connect to the Web, download information and read graphics-heavy files.

But consumer advocates worry that AOL's control of Time Warner could create a less competitive landscape that could actually reduce choices to consumers seeking high-speed access.

Until its acquisition agreement, AOL was leading a charge to convince regulators or courts to force cable TV operators — notably AT&T; Corp. — to lease their high-speed connections to Internet service providers, such as AOL.

The concern is that AOL will now abandon that fight and align itself with AT&T;'s position. Indeed, as part of its own proposed merger with the MediaOne cable company, AT&T; would get a 25 percent stake in cable systems owned by Time Warner, linking it to the AOL/Time Warner entity.

Case told reporters on Monday that the Time Warner deal will allow the marketplace, not the government, to decide how Internet service companies will get access to cable TV lines.

He did not elaborate. But several non-profit groups, citing the AOL-Time Warner deal, urged the Federal Communications Commission to consider requiring open access to the Internet.

"Steve Case is the Benedict Arnold of the digital age," charged Jeff Chester of the Center for Media Education, a non-profit group. "He's campaigned all across the country for open access. After he purchases access for AOL, he's no longer in favor of public policy."

But AOL's new executives say their aim is to make the world a better place by fighting social ills.

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``This is not just about big business. This is not just about money,'' Levin said during a Tuesday morning television appearance. ``This is about making a better world for people because we now have the technology and the instruments to do that.''

One of the goals, Levin said, is to plug the so-called digital divide, ``to try and make sure that ultimately those who can't afford it can get it.''

Case, 41, said he expected the proposed merger, which is subject to regulatory and shareholder approval, to have a quick impact by making richer content more readily available among other things.

``We're not talking about 10 or 15 years,'' he said. ``We work on Internet time. This is a company that's going to move fast. We want to see things every six months.''

AOL and Time Warner vowed to open what would be their vast cable system to online rivals. In so doing, they moved to take a debate over access to high-speed Internet pipelines out of regulators' hands and into the marketplace.

The deal is subject to regulatory approvals and the approval of AOL and Time Warner shareholders. The companies said the merger was expected to be finalized by the end of the year.

—The Associated Press contributed to this story

—Reuters contributed to this story