Using 41 MP in marketing speech is flagrant.
How is an undeniably accurate, relevant, and useful fact like the total pixel count "marketing speech"?
See what Nokia actually says quite prominently in PR like thishttp://europe.nokia.com/find-products/devices/nokia-808-pureview
not just in the white paper. Nokia puts clear emphasis on the ideas of (a) 7->1 downsampling to 5MP and (b) achieving "zoom" by cropping while using a small, bright, sharp prime lens. Nor do I see the slightest hint from Nokia of a claim that IQ will be comparable to that from a DSLR, so I do not see the relevance of your "comparison between large prints from a D300 and an 808"; that seems to be a straw man criticism.
More to the point, the latter feature absolutely needs a high total pixel count: a 5MP or 8MP or even 16MP 1/1.2" sensor would lose significant flexibly in a mobile phone where using a prime lens is a great advantage over a zoom lens. Crop-to-zoom is an essential part of camera-phone usage, making high total pixel count more relevant here than in compact cameras. In contrast, 18 million 1.2 micron pixels on a 1/2.3" sensor with a slow f/3.3-5.9 and f/3.2-5.8 zooms in some new Sony models is far more in the realm of marketing hype, because diffraction will almost always reduce resolution below what that 18MP promises.
What would you have Nokia do: not mention the fact of the pixel count at all, even though it is a key ingredient in the camera's zoom performance, and then try to explain the ability to maintain true 5MP resolution over a wide zoom range in contrast to competing camera-phones which "zoom" by cropping to under 1MP and then interpolating up, wasting space in a pretense of higher resolution?
This seems like the "anti-megapixel myth" at work, to coin a phrase.