I just noticed this new feature today on cruiseplum.com (an independent cruise search web tool).  It was added early April.  I've been anticipating them adding this feature to their site for a while now and now it's here!   You can now get email notifications for price drops on cruises of your choice based on a target price that you decide.  You can have up to 5 cruises with alerts set at any point in time.  I suppose you could increase that limit by creating another account with a sep