[thricedotted]

Here's the trend I see: all the browsers after IE pretty much go in order of market share. Safari isn't that special because it's the default on Macs, so even though its market share is only slightly above Opera's, the score there is dampened because there's still greater diversity in the people using it. But way fewer people are using Opera rather than Chrome or Firefox...I bet if you went back to the times Chrome/Firefox had a similarly sized market share, you'd see the same spike.

So it's not sampling bias, per se, but...I guess it's something along those lines?

[neilk]

Ah, now I see. It makes perfect sense. Think of it this way.

1. People who pioneer the use of alternative browsers always have high intelligence.

2. However, some browsers lack the ability to appeal to anyone beyond that initial market.

So know the graph is just saying things we already knew. Opera has a tiny fanclub, but the browser doesn't appeal to many people, or Opera fans are just bad at evangelizing to their friends. Meanwhile Chrome and Firefox have a much greater mainstream presence, and hence an attenuated average IQ.

So Opera's concentration among intelligent users isn't an indication of quality, but rather, some problem in their marketing approach.