Google Trends could be a very cool tool for Network Marketers.
Let’s look at search interest of Quixtar vs. Xango to see how they are trending against one another (Quixtar is Blue and Xango is Red):
As you can see, interest in Quixtar has been trending downward, while interest in Xango has been trending upward and looks to have recently passed Quixtar. This may indicate that Xango is a "hotter" Network Marketing company at this time.
There is also a cool little tool that shows what city has the most searches for a word. This might be helpful in determining what city to focus your energy on if you have a large organization spread across many cities.
Update: Click on the graph for the full view. The end is cut off. Sorry!