iFrames usage

Hi,

A customer wants me to use iFrames istead of regular links because he doesn't want the visitor to leave his site.

Ofcourse i'm 100% against such arguments.

Is there an official W3C statement around the usage of iframes?
What is the correct usage for iframes anno 2012?

HTML5 supports iFrames Link (http://www.w3schools.com/html5/tag_iframe.asp).

Though maybe use an <object> instead Link (http://www.w3schools.com/html5/tag_object.asp).