When customers buy software in a store, the source of that software is obvious.
Customers can tell who published the software, and they can see whether the package has been opened.
The Internet lacks the subtle information provided by packaging, shelf space, shrink wrap, and the like. Without an assurance of the software's integrity, and without knowing who published the software, it's difficult for customers to know how much to trust software. It's difficult to make the choice of downloading the software from the Internet. Marimba's Castanet communicates to customers the real identity of the publisher and assures them that the product has not been altered or damaged. Electronic content and software distribution over networks involves potential security problems.