WASHINGTON — Few people would dispute that one of the biggest contributors to the extraordinary success of the Internet has been the ability of just about anyone to use it to offer any product, service or type of information they want.

How to maintain that success, however, is the subject of a momentous fight that resumes this week in the United States Court of Appeals for the District of Columbia Circuit. The battle pits one of the largest providers of Internet access — Verizon — against the Federal Communications Commission, which for nearly 80 years has been riding herd on the companies that provide Americans with telecommunications services.

Verizon and a host of other companies that spent billions of dollars to build their Internet pipelines believe they should be able to manage them as they wish. They should be able, for example, to charge fees to content providers who are willing to pay to have their data transported to customers through an express lane. That, the companies say, would allow the pipeline owner to reap the benefits of its investment.

The F.C.C., however, believes that Internet service providers must keep their pipelines free and open, giving the creators of any type of legal content — movies, shopping sites, medical services, or even pornography — an equal ability to reach consumers. If certain players are able to buy greater access to Internet users, regulators believe, the playing field will tilt in the direction of the richest companies, possibly preventing the next Google or Facebook from getting off the ground.