NBC to Kohl: Americans had 'record' access to Olympics coverage

"We wonder if this policy is a harbinger of things to come should this merger be consummated, and whether requiring a pay TV subscription to access NBC internet content will be a standard policy in the future after this merger is completed," he said.

The Internet, Kohl said, should be a competitive alternative to traditional cable or satellite subscriptions, but NBC's apparent actions could diminish that potential.

In his response to Kohl's letter, Zucker said NBC spent close to $1 billion  covering the Vancouver Games. In an attempt to recoup those costs, NBC had three ways to offer coverage. More than 190 hours of programming were available on NBC's free, over-the-air network stations, with additional coverage on NBC's national cable networks (USA, CNBC, MSNBC).

NBC supplemented its coverage on NBCOlympics.com, where ad-supported video content was available as well as long-form content available only to subscribers who had paid to receive additional Olympics coverage via the NBC Universal cable networks.

After a certain time period, that subscription-required content was made available to everyone, Zucker said.

"NBC has long had a hybrid approach to televised programming of the Olympics," he wrote. "Without this hybrid approach to ad-supported broadcast households and (pay-TV) households, NBCU would simply not be able to bring our complete Olympics coverage to the American public."

The issue of tethering online video access to pay-TV subscriptions has gotten criticism as Comcast rolls out its "TV Everywhere" initiative, through which Comcast subscribers have access to additional content online.