IMO, what you call 'whisper marketing' (or word of mouth) is really what stands behind a product: substance.

No one is going to do this whisper/word-of-mouth marketing for the companies for free, if there's nothing in it for them. But, if the product can make them happy, then they will definitely share this fact for free to their families/friends.

Now, what makes people happy? What is the substance that propel these products?

iOS = Great UI/UX. Great content. Style & polish. Great brand name.
: These things are quite universal and they work on a significant portion of the potential consumer base.

Android = Great UI/UX. Good content. More open and capable than iOS. Great brand name.
: Again, these are universal traits, acceptable by just about everyone allover the world. One can also argue that they ride on the coat tails of iOS.

maemo = FOSS, very open and robust, good content for the *nix crowd (but not so much for the general audience), good UI/UX for the most part (but you may have to tinker with things under the hood for some of the tweaks), great form factor (again, for the techy, maybe, but not so great for the masses).
: There are some good potentials, BUT there are too many 'buts'...

IMHO.