Google Trends is a cool tool. It has several limitations (a subject for another blog post) but you can get some interesting information with a few simple queries. I wanted to find how heavily XML is used by various programming languages (this is not real use, but an indicator of use). The assumption is that if I can find a query where a language and xml are typed together "java xml", it means there is an interest in using java with xml. So here is a query I tried.
"java xml, perl xml, php xml, ruby xml, python xml"
And here are a few trend graphs:
This is for all years. One of the limitations of Google Trends is that I cannot choose a range (from 2004 till now, from 2005 till now etc.)
Here is the trend in 2005.
And a minor variation Java XML and AJAX. This is pretty revealing.