http://msmvps.com/blogs/paulomorgado/archive/2007/05/14/update-extension-methods.aspxLooks like I was way wrong in here and here . I had thought that from the top of my head because I tried to use Array.IndexOf as an extension method and was surprised to see that it wasn&#39;t an extension method. It presented a good opportunity to playenCommunityServer 2008.5 SP2 (Build: 40407.4157)http://msmvps.com/blogs/paulomorgado/archive/2007/05/14/update-extension-methods.aspx#905318Tue, 15 May 2007 09:29:18 GMTd67277c4-116b-43f1-b688-e9ef184ea916:905318DotNetKicks.com<p>You've been kicked (a good thing) - Trackback from DotNetKicks.com</p> <img src="http://msmvps.com/aggbug.aspx?PostID=905318" width="1" height="1">http://msmvps.com/blogs/paulomorgado/archive/2007/05/14/update-extension-methods.aspx#904573Mon, 14 May 2007 23:35:43 GMTd67277c4-116b-43f1-b688-e9ef184ea916:904573Extension methods missing from System.String in the .NET Framework 3.5 (Beta 1) - Paulo Morgado<p>Pingback from &nbsp;Extension methods missing from System.String in the .NET Framework 3.5 (Beta 1) - Paulo Morgado</p> <img src="http://msmvps.com/aggbug.aspx?PostID=904573" width="1" height="1">http://msmvps.com/blogs/paulomorgado/archive/2007/05/14/update-extension-methods.aspx#904571Mon, 14 May 2007 23:35:00 GMTd67277c4-116b-43f1-b688-e9ef184ea916:904571Extension methods missing from System.Array in the .NET Framework 3.5 (Beta 1) - Paulo Morgado<p>Pingback from &nbsp;Extension methods missing from System.Array in the .NET Framework 3.5 (Beta 1) - Paulo Morgado</p> <img src="http://msmvps.com/aggbug.aspx?PostID=904571" width="1" height="1">