In this article, the author talkes about no-touch deployment and ClickOnce deployment in its ClickOnce topic. Basically, ClickOnce deployment introduced by Whidbey is an updated version of no-touch deployment introduced by .NET 1.x. It solves some limitations of no-touch deployment and provides more choices during the process.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_vstechart/html/vs2004_intro.asp
