It what appears to be an unofficial agreement, Facebook and Apple will honor each other's currency for games running on their platform as long as the cost of virtual goods is the same on both platforms.

It's a sort of unofficial pact mentioned by Ubisoft's VP of Digital Publishing to Tricia Duryee of AllThingsD. Why's this a big deal? As Duryee cleverly describes the existing state of things for game players, "it's the equivalent of traveling in Europe before the Euro." By being able to purchase the same goods across both platforms, you can keep things in sync no matter where you are. However such a concession by Facebook would ultimately be a relatively large one.

While many people have projected Credits to become the defacto currency for the web, being effectively forced from the iPhone could mean that Facebook will be limited to just that, the web. The key next steps for Facebook will be to forge partnerships with online media publications and other web-based properties looking to sell content in an effort to gain a dominant position for their currency. For the time being, games are where all Facebook Credits transactions take place and being interoperable with other currencies (such as Apple's) will ensure that users feel comfortable making purchases with them.

While users won't be able to make virtual good purchases within Apple games with Facebook Credits, at least gamers making purchases on Facebook will know those purchases will be honored when they're on the go with their iPhone.