Here's an excerpt of AdWeek's piece on the data:
According to Nielsen, NBCOlympics.com, which will stream over 2,200 hours of live competition, drew 4 million-plus unique users this past Saturday. That's up from the 2.7 million users who logged in the previous day.
Yahoo!'s Olympics site, which does not offer any live footage, attracted 3.3 million unique users on Aug. 9, bringing it within 684,000 of NBC's traffic. Third-place finisher AOL Olympics saw over 1 million users that day.
Meanwhile, NBC officials are reporting that its Olympics coverage is performing far better than during the summer games four years ago in Athens, Greece. NBC's site recorded 70 million page views on Aug. 8 (opening ceremonies), a whopping 10-fold increase versus the 7 million page views generated in 2004. In fact, those 70 million page views bested the Athens Games' strongest traffic day by almost 50 million, said NBC.