In reviewing the reactions of our user base to all the great apps being built by the community, we have been moved to give end users more configuration options in how they interact with apps. We have added a new privacy communication setting to users' profiles and slightly restricted how apps may send messages and comments. As originally deployed, an application could use the MySpace postTo extension to send messages to any user in the MySpace system, subject to that user's spam and privacy settings. To curtail abuse (occassionally a spammy app makes it thru the review gauntlet) we have tightened this up so that apps may only send messages to a viewer's friends.
Additionally, users may now disable communications from all apps (Edit Profile > Account Settings > Applications > Application Communication Settings). If an app attempts to send a message/comment to a user who has indicated they do not want communication from apps, upon confirmation of the postTo message the app viewer sees an error dialog "Undeliverable Message or Comment" and if a callback handler is attached it will receive an error response.