I'm looking for a product that used to be offered by Cory Rudl and his successors several years ago called Desktop Marketer. It was a program that allowed marketers to communicate directly to their subscriber's desktops. Subscribers installed a piece of software that resided on the lower right toolbar of their PC and would ping the mother ship at set intervals. Marketer could post a message on the server and it would appear in the toolbar of the recipients, flashing until they opened and read the message. Arguably, it was an early version of Twitter, but the message center the customer installed belonged solely to the marketer and no other messages from other vendors would appear.
Does anyone know if that product is still around being marketed by someone else, or if something similar is on the market? Barring that, for those of you who are coders, how difficult would something like this be to create?