In my last blog entry , I wrote about a Zillow-Salesforce mashup up I was writing.  It is now complete.  You can find the complete article and the code here.  The article is meant to be used as an illustrative example of using REST based services on Force.com, if you are intending to do build something more serious with Zillow, please be sure to read their terms of use.

For an example of a really cool enterprise grade mashup take a look at  Xactly Rewards. This application combines their Salesforce.com application with Google, PayPal and Amazon (wow!) on Force.com to build an on-demand incentive reward and fulfillment system.   Phil Wainewright has an excellent writeup about this application on his blog.  He has this to say about the power and potential  of such mashups.....

This five-way mashup is a substantive proof point for applying mashups to enterprise applications. It pools the disruptive economics of at least three separate giants of on-demand: Amazon, PayPal and Salesforce.com. Will any ZDNet reader dare argue with me that you could/should do this in-house and do it better and cheaper? It’s simply not tenable. Nor is it any more practical to think of implementing a similar mashup to Amazon, Paypal and the rest from an on-premise application — leaving each individual customer to negotiate their own gateway access to Amazon, Paypal and the rest, along with the necessary security precautions. It’s a recipe for multiple implementation disasters.

Mashups open up a whole new market for innovative ISVs without a huge upfront investment.