Redmond’s App Contest announcement is either: a) a scatter-shot attempt at playing catch-up within this space (particularly in light of Google announcing / hitting / passing the 10 billionth app download benchmark; b) a brilliant marketing ploy (no offense but this is unlikely) and/or; c) a combination of desperation and marketing spin in order for Microsoft to try to actually become relevant within this space.
(Source) WSJ: http://goo.gl/yNhUx