Google Related Research Feature

I found a good and simple Google search feature that could be potentially useful to teachers and students:
http://www.blindfiveyearold.com/google-related-searches
The above website introduces quite nicely.
I did a search with the key phrase "Lusitania ww1."  I also clicked on "more search tools" on the left of the Google search screen. The result is that I get the following related key phrases to search for similar content on Google search:

Related searches for Lusitania ww1:

1. sussex pledge
2. zimmerman note
3. zimmerman telegram
4. treaty of versailles
5. unrestricted submarine warfare

1. lusitania ship
2. lusitania sinking
3. lusitania
4. lusitania world war one
5. lusitania ww2   

Besides the above, I also got a list of websites related to this topic: