Amazon just announced this morning that come May, the company will be rolling out a virtual currency program known as Amazon Coins. Owners of Amazon's Kindle Fire tablets will be able to use the virtual funds to purchase apps and games within the Amazon Appstore. In-app purchases will also be possible with the new currency, a structure that Amazon hopes will benefit app developers directly. Amazon apparently feels that if its app users have an simple, fun option for buying things in their Appstore, developers will almost inevitably see higher revenues as a result. As it happens, despite the fact that developers...