If true, that would take the wind out of one of Apple’s last bragging points — a point that Tim Cook reiterated just last March at All Things D: The iPhone may have lost the lead in terms of market share, but iOS continues to dominate the Internet in terms of Web usage.

According to Cook, iOS beats Android in global Web usage by better than 2 to 1 (58% to 25%). According to StatCounter, however, Android leads iOS 29% to 25%.

How could the two stats be so far apart?

Two reasons.

First, Cook relies on data provided every month by NetApplications, a Sunnyvale, Calif.–based outfit that counts the Web usage of both smartphones and tablets. StatCounter is counting only smartphones.

Second, NetApplications weighs its data according the Internat usage in each country surveyed.

StatCounter, by contrast, uses “no artificial weighting,” as it proclaims proudly on its FAQ. In other words, data from a country with few Internet users (like Burma, where only 1.1% of the population is online) is treated the same as a country with heavy Internet usage (like Norway, where 95% of the population surfs the Web).

The result is two very different pictures of Internet usage, as shown below.

StatCounter:

NetApplications: