This kinda of hit me after reading this question, mainly because it's true. As a webmaster I don't care what language you are hosting your website on, I only care if its relevant to mine. The more subjective and language agnostic it is, the more likely the question is going to apply to something I am working on, some-way, some-how.
As soon as you ask a question about
.net this or
.asp that, I am going to ignore it, because its not
.php. (I already have my ignore tags in place.)
Most likely why SEO, hosting and payment processing questions are ranked highest, because it applies to well.. everything.