Grok was coined by Robert Heinlein, in 'A Stranger in a Strange Land'. It had a meaning of deep & mystical understanding. Good name for a visualization tool.
This was a commercial product, but now it runs in Java for free (ad supported). They're using Yahoo for results. I've tested in Firefox PC, I'll try Mac in an update.
The above search is on my last name; a handy testing tool for me! :-).
Grokker is certainly interesting. I'll play with it.