Keynotes are fluid until about 24 hours before they are given. Over the course of the months before you'll hear lots of rumors, some baseless and some due to the facts of the time. The key point any competent executive understands is the business dynamics can change at a moment's notice based on various factors that impact the message of the moment. The March keynote focus changed around the turn of the year to be purely non-Mac centric to allow the new Macs to fill the line up for June WWDC. The June line up is now approaching but is oversubscribed so there's a better than evens chance that there will be a quiet Mac announcement to not steal the June WWDC thunder. As I say, stay tuned, you especially!