"As the Web has evolved over the years, businesses and developers have adopted the Web as a primary development platform. A term was coined to describe the new era of web applications: Web 2.0. Web 2.0 specifies that web applications should be composed of original developer efforts and should consume services offered by other companies and developers. Web 2.0 applications are partially designed on the publisher-subscriber paradigm and integrate media and animation."
"Microsoft began experimenting to extend ASP.NET AJAX to further gain control over the client-side computing environment to improve the technology…"
(Shannon Horn in 'Microsoft Silverlight 3: A beginner's guide,' p. 43 TMH)