The writer misses the fact that Apple has a more general and consistent concept of "sharing" (and has had consistently for nearly a decade -- before iOS and before the iOS sharing icon) than the others.
Share -- exemplified by iPhoto -- means share byanymeans (e.g. email, youtube, twitter, facebook, burning a DVD). Thus, Apple's icon makes perfect sense -- more sense than the Y -- based on this. You might be sharing with one specific person, or everyone. The point is that you're sending stuff OUT.
Most of the others treat sharing as something special that is "distribute by any method except the other things we have icons for".
Share -- exemplified by iPhoto -- means share by any means (e.g. email, youtube, twitter, facebook, burning a DVD). Thus, Apple's icon makes perfect sense -- more sense than the Y -- based on this. You might be sharing with one specific person, or everyone. The point is that you're sending stuff OUT.
Most of the others treat sharing as something special that is "distribute by any method except the other things we have icons for".