There used to another equally useful tool called Google Insights for search, but since September 27, 2012, it has been merged together with Google Trends.
In other words, both Google rank and Google Insights are packed together as one more user-friendly tool.
This revamped tool is said to be more powerful and useful to let you research and predict search terms.
For those of you who want to do your keyword research, try out this newly-revamped Google Trends.