I’ve been thinking and writing (here, here) a lot recently about the promise of cross domain functionality.
For the first time, web apps can aspire to be more than just destination websites. Embedded Flash widgets and viral “poking” apps have given us a taste of how content can spread on its own from page to page.
But I see this sort of “viral for the sake of viral” as small beans compared to the larger prize enabled by an API / Platform driven Web. What’s more interesting to me is the idea of owning a feature that provides cross domain value to its users. A successful cross domain feature will allow content contributed on one domain (say Facebook) to available to the contributor on another domain (say MySpace). A single login will give the user access to that feature’s functionality and content wherever the service is available – blogs, social networks, API partners, etc.
Shelfari (on just $1M in funding), is doing a pretty good job of preserving a unified experience in the books vertical. If I add a book to my shelf on Shelfari.com, it shows up on my MySpace and Facebook Shelfari applications.
Disqus, a company that I reviewed here, is also attempting to own a cross domain feature – blog commenting. If I receive a quality point on a comment that I made on A VC, that reputation point gets associated with my Disqus account wherever I choose to comment.
My own company, RateItAll, is attempting to own the feature of consumer reviews across domains.
In addition to things like making reviews that you post on Facebook available and shareable on MySpace and vice versa, we are also preserving reviewer reputation across domains, and allowing a single login / cookie to enable participation on RateItAll.com, on any blog that uses our widget, on SNS, and on any site using our API. As a very simple example, if you add our Facebook app, you will be able to post a review of Sexy Widget via the rating widget in the top left hand corner of this blog without logging in, and that review will be accessible on your Facebook account.
We’ve also just turned on some cross domain functionality between MySpace and Facebook that we think is pretty cutting edge.
Here’s how it works:
RateItAll’s Compatibility Application (FB, MS) allows user to check their compatibility with their friends by rating items within various categories; beer, Web 2.0, politics, TV, movies, etc. For example, I rate ten beers, you rate ten beers, and we crank out a “beer compatibility score.” Our compatibility tests are drawn from user submissions to RateItAll’s large destination Web site.
Once a user completes a compatibility test, not only are they displayed their compatibility scores with their friends, but also “global” compatibility scores – the user’s compatibility with people who are not currently their friends.
And here’s where it gets interesting – your global compatibility results on the Facebook App include not only other users on Facebook, but users on MySpace as well. So by taking a compatibility test on Facebook, you can find people on MySpace that share your tastes. For example, in this screenshot, all of the links in the "Global Results" section are links to MySpace profiles:
We think it’s a pretty cool example of a single user experience that spans multiple domains. In this particular case, we are proving people discovery of folks with similar interests from a pool that includes both MySpace AND Facebook.
Furthermore, any compatibility tests that you complete on Facebook will also be available to you on MySpace. Any ratings and reviews that you post on Facebook, MySpace, RateItAll.com, or any of our read / write rating widgets will be available to you for sharing via any of our apps or our destination site.
Oh yeah, you can also access our entire database of millions of reviews on either Facebook or MySpace.
One login, powering consumer ratings for everything, on any domain, with people and content discovery tools that span domains.
Make sense?
If any SW readers have a few minutes and would like to try out our cross domain functionality, you can do so via any of these entry points:
Here’s our Facebook App:
http://www.facebook.com/apps/application.php?id=18480724104&b
Here’s our MySpace App:
http://www.myspace.com/rateitallreviews
And here’s the “hub” of the network, RateItAll.com.
Until recently, it was seen as a snub if somebody called your company "a feature." I don't think it's so much of a snub if you can grow to become a feature for a significant portion of the web.


