I don't know much about the respective businesses, certainly not enough to comment, but this will effect on the way that the community view Nokia even with a somewhat trivial announcement.

Up until this point Nokia seemed to be the leading proponent for open in its adoption and continued work of a POSIX based Linux implementation for its smartphones in the shape of Maemo/MeeGo and opening the once-irreversibly entrenched symbian. A great distinction from other market players.

I can't see MS trying to break into the feature-phone market, and don't expect MS to suddenly adopt open ideology, and assume that Nokia would be conspiring to release WP7 on smartphones -- being that phones is practically all that they do in volume.