According to a new article on the W3Tech.com site today, around three quarters of all websites are based on PHP. They've run their own survey to gather the results about the use of several different languages like ASP.NET, Java, Ruby and, of course, PHP.
Our server-side programming language survey shows that a very remarkable 74.9% of websites use PHP, slightly increasing in the last year. ASP.NET technologies (presumably mostly C#) come in second, and a few percentages are left for Java. That's about it. The variety of programming languages used to develop websites is surprisingly small, considering that everyone and his dog develops websites these days. There is a lot of talk in the IT blogoshere about alternative languages such as Ruby and Python, but their real world usage is tiny compared to PHP.
They talk about some of the contributing factors to these numbers including the wide use of various PHP-based content management systems, the balance of high traffic versus low traffic sites and some breakdowns according to operating system, geographical area and a hint at how their survey operates to find the systems using PHP.