Facebook opens APIs for Mashups –Why build another social site if you can harness an existing one?

Facebook opens up APIs for Developers
If I were to start a company that was focused on building a social site around a particular segment (such as cars, food, drinks, or anything else that interests me), I’d consider tapping into existing social networks. Facebook could be just that, as developers could create new applications that could mash with their data (profiles, images, friends and events). Heh, I love how Marc Canter gets so excited about open systems, “I told you so” he says. Learn more at this launched Facebook Developers.

Currency now available
It appears that they’ve also launched a new product called Facebank, which adds in currency to this model –there could be money to be made here. Although there’s already typical marketing being deployed such as Chase’s credit card campaign, (more info here) this will create some unique business models that tap into user to user transactions.

Could this impact Intranet/Extranet Developers?
Let’s think about intranets too, we know that Facebook has released it’s product for businesses to use, not just colleges, if done correctly, these APIs could replace many stale corporate intranets (esp if folks have to rely on a centralized group to update content) and it could tie to other tools such as linkedin, events, calendars, contacts, etc. Think about the rich profile information an employee could put on their Facebook account that could show the skills, projects, they’ve completed.

Web Strategy Question: Build new vs Harness existing
I begin to question why build and brand a new social site when you could harness an existing one? Love to hear your thoughts.