Will mashups will be like air?

A mashup of San Francisco's BART station maps and timetables.

Are we now finally entering the age of programmatic sites driven by other sites, i.e. the age of the 'mash-up'?

Although more and more websites are now offering APIs that allow you to access the underlying data programmatically, very few of the 'mash-ups' that have arisen from these have had popular appeal. Google Maps is the exception, managing to offer an API that allows for every person and thing in the world to be easily represented on a map. Web sites that offer real estates to restaurants now look behind the times if they don't use this technology.

However, Groundswell is claiming that their prediction that social networks will be like air is about to come true: Facebook has announced that it will be launching Facebook Connect, a way to connect your Facebook identity to other sites. Imagine having your book reviews on Amazon tied to your Facebook account and seeing your friends' Amazon reviews via their Facebook profile. In many ways, if Facebook Connect works as well as it sounds, it could be like the Google Maps of the social networking world.

Both Google Maps and Facebook Connect provide an element to existing sites which would be difficult for these existing sites to do themselves. A restaurant site does not want to manage data on maps or build fancy social profiles of all their users. Perhaps this model of 'outsourcing' elements of interactivity that are non-core to a site is the way to do mashups?