Point 1: Internet Explorer (at least as of version 6) doesn’t even know what to do with the abbr (abbreviation) tag, and ignores it entirely. Here’s how to style <abbr> in IE
Point 2: What’s the difference between an abbreviation and an acronym anyways? HTML is not an acronym; it’s an abbreviation, or more specifically and initialism. Here’s an article to help you tell the difference.
* This post was originally published on August 16, 2006 at http://www.csb7.com/blogs/whyblogwhy/2006/08/16/abbr_in_ie