Microsoft may have retired Internet Explorer 6 (IE6) last week, but it's still keeping track of the ancient browser's user share on a death watch-like website that's been running for more than three years.

IE6 launched in August 2001, about two months before Windows XP shipped. Microsoft issued the final security update for IE6 on April 8, when it patched two critical vulnerabilities in the browser, then retired the browser as its patron, Windows XP, also went to pasture.

According to the still-live IE6 countdown website, which draws data from analytics vendor Net Applications, IE6 accounted for 4.2% of all browsers used in March.

In 2011, when it fired up the countdown site, Microsoft set a goal of reducing IE6's global share to less than 1%. It has yet to hit that benchmark. Instead, the browser has hung in there: IE6's user share last month was actually about five times larger than that of IE7, its 2006 successor.

The Redmond, Wash.-based software vendor expended significant PR capital to vilify IE6 during a five-year campaign to persuade users to upgrade to newer versions. That campaign started in 2009, when a Microsoft manager famously said, "Friends don't let friends use IE6." It continued in 2010 with claims that the browser was past its expiration date. The same year, Microsoft sent flowers to a mock funeral hosted by a Denver-based Web design group. In early 2012, Microsoft declared IE6 dead in the U.S. after the browser's user share in this country fell below 1%.

As of March, IE6's user share in the U.S. was 0.2%.