TIOBE programming community index is an ordered list of programming languages, sorted by the frequency of web search using the name of the language as the keyword.[1] The index covers searches in Google, Google Blogs, MSN, Yahoo!, Wikipedia and YouTube. The index is updated once a month. The current information is free but the long term statistics over many years of observation is for sale. The index authors think that it may be valuable when accepting various strategic decisions. TIOBE focuses on Turing complete languages, so it does not provide information about the popularity of, for instance, SQL or HTML.
According to the site, TIOBE index is not about the best programming language or the language in which most lines of code have been written,[2] However the site does claim that the frequency of searches may reflect the number of skilled engineers, courses and jobs worldwide. Tim Bunce, author of the Perl DBI, has been critical of the index and its methods of ranking.[3]
For many years, TIOBE has been a subject of flame wars. In particular, decrease of Perl popularity (while it is in general still ranked high) raised discussions that maybe this language is "dying,"[4] followed by wide negative response from the Perl community. Similarly, the growth of Python has been discussed as a success in the Python community, although the sharp decline in Python's popularity that occurred during 2011 was studiously ignored. Java staying at the top has been interpreted as a success, but some decline over many years has also raised a discussion if this is a dying language. TIOBE indicates that C# is growing in popularity as it has been rising on the chart, and is currently in fourth position. TIOBE index does not give a particularly high rank to Fortran, Eiffel and some other notable languages.
TIOBE index is sensitive to the ranking policy of the search engines on which it is based. For instance, in April 2004 Google performed a cleanup action to get rid of unfair attempts to promote the search rank. As a consequence, there was a huge drop for languages such as Java and C++, yet these languages have stayed at the top of the table. To avoid such fluctuations, TIOBE now uses more search engines.