There are a number of developers creating social applications leveraging APIs which can cause developers to recreate common components. Zembly recently launched to help facilitate collaboration among developers. I spoke with Zembly founder Todd Fast and he said he wants to "be the Wikipedia of social applications." What he means is that he wants to create a development community with Zembly where collaboration runs rampant thus saving rework and time. I think Zembly is a great idea and could save developers from novices to experts a lot of time while facilitating collaboration.
Zembly is backed by Sun Microsystems, and targets applications for Facebook, OpenSocial, Meebo, and other social platforms. I got a chance a demo of Zembly and captured it as episode 32 of SOMEWHAT FRANK TV. In the video (below) Todd Fast walks through the basic idea behind Zembly and even updates a Facebook application using common code components created by the community.