The process of selling and promoting digital products is quite a bit different to how you would sell and promote physical products from an ecommerce website.
Different audience to traditional products which are typically sold via an ecommerce site
capturing those in the buying process.
Digital product purchases on the other hand tend to be more of a personal purchase,
targeting an audience with particular interests.
They might therefore be willing to make a purchase having discovered the product, without initially seeking to make a purchase.
Price is generally less of an issue for digital products as they generally cost much less to create and therefore can be sold for less.
The way in which they are sold also can be quite different. With a physical product purchase, you typically visit an ecommerce style site.
A digital product on the other hand,
especially if it is a one-off item may have a dedicated page/website that does not generally resemble an ecommerce style site.
Sometimes these types of products will also be sold via a specific platform
(the iTunes store for example).
There is also a fundamental difference in the way each type of product is packaged to be sold online.
With physical products, you will often base the purchase on the product itself; packaging rarely will affect this type of purchase. Digital products in some cases seem to be driven more by design initially.
How you package the product up can have a considerable effect on initial interest and therefore can result in more purchases.
You see this quite often with digital purchases when they include lots of “added bonuses” to try and encourage a purchase.