Google surpasses Yahoo--for a second time?

Google passed Yahoo in its share of monthly visitors in the United States for the first time this April, buoyed by growth in search and YouTube videos, However, underscoring the variability of this sort of measurement, which extrapolates overall data from the usage of a "panel" of users at home and work, Google sites had 141.1 million unique visitors in April, a tad ahead of Yahoo's 140.6 million. Microsoft was in third at 121.2 million, with AOL at 111.3 million.Yahoo leads its rivals with 3 hours and 9 minutes per month, but AOL owner Time Warner leads Yahoo at 3 hours 40 minutes per month.Microsoft's usage was 2 hours and 17 minutes, and Google was 1 hour and 47 minutes.