I would say yeah, the Kindle, combined with Amazon's ebook ecosystem, is pretty much the perfect delivery apparatus. The variety of titles is rather astounding, and
Rule 34 definitely applies. The ease of getting "home made porn" (fanfiction) onto the system also helps.
Of course what that has done for Kindle sales, if anything at all, is speculation. My guess is that the privacy aspect has helped push sales a bit, but how much is just a guess.