...and good riddance. United States Patent No. 4,558,302 expires today. Better known as the LZW patent. This is the technology behind the common GIF file.
As of the 21st, U.S. companies and organizations that produce software and hardware products that use the GIF format (and other LZW-related technologies) will no longer be required to pay license fees to Unisys for doing so. However, LZW patents are still in effect for Canada (until July 7, 2004), the UK, France, Germany (expiring June 18, 2004) and Japan (expires June 20, 2004).
Will the expiration of this patent be the death knell for PNG? I don't think so. PNG is still the graphic format we should be using (although it currently doesn't support animation like GIF does -- MNG is the answer for that). But the quality is superior and offers transparency. Sadly, it's not as widely supported as GIF (talking about you, Internet Explorer).