In case you haven't read, Apple has made two significant changes to the app store over the past few days.
1) App Title: Once entered, you can no longer change the title of an app. It can only be changed again if you resubmit a new app for review, or your app is in the "rejected" state. This applies to all current apps. All existing apps are locked with their current titles.
2) Keywords: There's a new keywords field for every app. These keywords, along with the app title will be used for searches in iTunes. Once entered, keywords can not be changed until you resubmit a new app for review (or the app is in the "rejected" state), so make sure you choose your initial keywords wisely! Keywords are also limited to 100 characters (including the comma separators).
I'm a bit surprised about the app title being locked without any prior warning. It seemed to be a pretty common occurrence for developers to append an "On Sale" or "50% off" as part of the app description when they were having a temporary price reduction and now this will be locked as their app title until they submit a new app.