Web services, DoubleClick, Akamai and even Netscape in Web 1.0 were the first widely deployed predecessor to what is now called "mashup". Their seamless content delivery network integration capabilities is a central component of Web 2.0

Web as platform example from O'Reilly:
Google began its life as a native web application, never sold or packaged, but delivered as a service, with customers paying, directly or indirectly, for the use of that service. None of the trappings of the old software industry are present. No scheduled software releases, just continuous improvement. No licensing or sale, just usage. No porting to different platforms so that customers can run the software on their own equipment, just a massively scalable collection of commodity PCs running open source operating systems plus homegrown applications and utilities that no one outside the company ever gets to see.

Web 2.0 permits the building of virtual applications, drawing data and functionality from a number of different sources. Web site owners are increasingly resembling software companies as in they generate traffic,sales, and encourage add-on products and Web services. This puts a great deal of power in the hands of outside individuals and transforms Web sites into programmable machines.

The data and metadata as is contributed by its users. Feeds and content tagging are other forms of distributed data.