Funny, after the last two comments, I guess I'm playing devils advocate. In my many years as a professional programmer, I can't say there are many "real world" (AKA, not Brainf*ck) programming languages that are popular while being truly awful. Frankly there are two, IMHO.
- Objective C
PHP rose to prominence simply because it was free and part of a free stack of technologies (LAMP) at a time when alternatives like Coldfusion, JSP and ASP.NET, could have thousands of dollar price tags. PHP wasn't popular because it was good, simply because it was free. Now years later it only exists because of the massive amount of legacy code that has been written on top of PHP due to it's early traction. Point blank, it's still a terrible programming language.