I found this article very good. It seems that there are some characteristics which did not get the deserved attention. What is really great, is that Web2.0 represents a return to the essential principles that guided the Web.
- Open Source: Yahoo was built on the foundation of open-source operating system(BSD Unix) and open-source language(Perl). The core of the Web was (NCSA Mosaic browser, NCSA and CERN HTTP Servers)
- Collaboration: Tim Berners Lee inventor of the World Wide Web and the leader of DIG put an original design for the Web to enable researchers to collaborate.
- Simplicity: we can find a lot of web2.0 products very elegant, simple, and focusing on only one single point; "make a single focus and do it well". This isn't an innovation. the RocketMail was one of the first major free webmail services, and it was focusing just on "e-mail".
- Architecture of participation: Epinion.com is a review site that was established in 1999. we can see now the success story of Amazon and eBay
- Lightweight programming model: many of the Web1.0 generation were built using scripting languages (example: Perl used in yahoo). Large companies used widely the complex web services stack and forgot the REST which was originated in 2000. (Amazon provides the web services in both forms SOAP and REST)
- Social Software: in 1994 Match.com was started. The "social software" was called "viral market".