900,000 American homes relied solely on the web for TV in 2008

"Some 900,000 U.S. homes didn't pay for TV and relied solely on Web TV last year, according to estimates from consulting firm Parks Associates, which projects that the number will grow this year. And 8% of adults now view television shows online at least once a week, up from 6% who did so in 2008, according to a survey by the Leichtman Research Group. The same survey found that 8% of adults who watch video online now watch TV less often."
Source: Parks Associates, cited by the Wall Street Journal, 28th May 2009