Recently, Google launched Google Insights. Like with Google Trends, you can just type in a search term to see search volume patterns over time, as well as the top related and rising searches. You'll also have the ability to compare search volume trends across multiple search terms, categories (commonly referred to as verticals), geographic regions, or specific time ranges. Great for marketing people.
Below are some examples specific to Drupal ...
— Dries Buytaert
Dries Buytaert is an Open Source advocate and technology executive. More than 10,000 people are subscribed to his blog. Sign up to have new posts emailed to you or subscribe using RSS. Write to Dries Buytaert at email@example.com.