PDF is an open standard (ISO 32000-1:2008) file format for document exchange created originally by Adobe Systems. I decided to check-out more on PDF and started off by keying in www.pdf.com in my browser's address bar. Lo' and behold! Turns out the domain belongs to a certain EDA company - PDF Solutions, Inc. Call it identity crisis or lack of foresight, but sure goes down as a classic WTF.