Open Everything: My previous post on Google Maps relates to this discussion. API mashups do appear to be the future of web applications. Here is a quote from the posted link:
"Application mashups (not to be confused with the music by the same name) are combinations of already availible APIs in a productive and useful - and usually cool - state. For example, the Google Maps interface allows you to enter in your own addresses to plot. Using this and some zip code data from the popular site 'Hot or Not', there's been an interactive map that shows users' locations. This simple example shows the real power that some of these mashups have, and it's all thanks to the open sharing of information that is offered through their APIs."