You are right:
The ratings are calculated by counting hits of the most popular search engines.
The search query that is used is +"<language> programming"
- From this month on we also measure the hits of Google Blogs. The languages that benefit from this are Java, Visual Basic, Ruby, and VB.NET. On the other hand, Ada, D, dBase, and Fortran have a lower rating now because they are not popular in blogs.
- There was a funny mail from Marcelo Barros de Almeida. He suggested to search for the query "<language> sucks" (sorry for this term) to get a feeling about languages that are unpopular. The top 5 is 1. Java, 2. PHP, 3. C++, 4. C, and 5. Ruby.
Ok... This explain the high mark of Visual Basic over Perl.
Now, I will go to my blog page and fill it with "Perl programming"... :-)