I looked at each language tag, and then went to the top few tags that were framework-like. This is total tags, not overlap or unique. I didn't attempt to categorize iPhone or Android questions.
python 70,179 django 21,775 google-app-engine 7,328 (includes Java version)
php 138,670 wordpress 8,955 zend-framework 7,510 codeigniter 5,599
java 149,995 spring 9,045 jsp 6,531
c# 207,260 .net 88,339 asp.net 87,495 asp.net-mvc 25,790
objective-c 50,334 cocoa 13,256
So,ruby-on-rails has more questions than any other framework except .net / asp.net or jquery. ruby, on the other hand, has far less questions than any of these other languages.
Is this unique to Ruby, or does this happen to other languages as well? – @Andrew Grimm
It's unique to Ruby, at least among the languages popular on this site.
Or just a really popular framework? – @Michael Mrozek
It's a really popular framework.
If Ruby is the programming language for which this happens, then it may indicate that the Ruby ecosystem may have some problems. – @Andrew Grimm
I don't think we can rule one way or the other on this, based on this information. The "really popular framework" theory seems sufficient. There are also more ruby -ruby-on-rails questions than there are perl questions, for example.