I wrote a Perl script to, from a keyword list, get the popularity of all the words or phrases in each line of the list.
To get the popularity of any keyword I get the Google results searching for that keyword and then I parse the Google result.

I repeat this for all the keywords in the list saving the data to a database.
The result is a list with a lot of words, keywords or phrases and the popularity of each of them according to Google.
There are a lot of things that you can do parsing Google results, the amount of information you can get is huge. You only need to understand the results and know what you are searching for.
And this isn’t only for Google, parsing the results of distinct search engines, news sites, social networks, etc… the information you can get is infinite…
You can use the online version of this tool here: Keyword popularity tool
Or read my first post about this webmaster online tool here: Online keyword popularity tool gives interesting results
Could you tell me the popular word of phrase that most of people type when searching website?