This test determines if your page has styled markup such as basefont, center, font or u. These style markup tags are considered dated and require additional processing time to render. Best practice dictates that all style related information should be contained in CSS files and not be included in amongst markup.
Checking for styled markup
This test checks to see if styled markup tags are detected on the page. These include basefont, bdo, center, del, dir, font, ins, menu, s, strike and u. If any style markup tags are detected on the page then the test reports a FAIL.
If you receive a FAIL for this test, you should consider moving all your styling data to CSS files instead.
This test is based on a YSlow best practice. See http://yslow.org/faq/ for more details.