The NFL is warming to the idea of delivering live American football coverage to fans online. After its historic free no-pay-TV-subscription-required live stream of a regular season game last October on Yahoo, rumors have been swirling about NFL’s future on the Web. Last week, the annual NFL Super Bowl game was delivered online directly to TV sets for the first time ever, marking a new chapter in the transition to Internet TV. That game drew 4 million unique viewers online to watch the game, and the average viewing session for the game was 101 minutes. That’s an outstanding number, compared to the 1.3 million that streamed last year’s Super Bowl via NBC. Last year’s live stream had a Nielsen equivalent…