Don't forget the USA is a huge place. Where I work half of the advertisements are in Spanish. Most of the Americans in IT that you would talk to usually speak only English but in Los Angeles a large percentage of residents speak Spanish.

So If I did a website for a local business I would actually have to Localize it and in some cases the majority of hits would be for the Spanish content. 

Why prefer c# over vb.net?  

It's simple : it's all about the keystrokes!  C# is a more concise language and not as verbose as vb.net, which results in quicker coding.