It’s been while since the last update on googleVis. Well, the Google Chart Tools are fairly settled now, but some time ago Google added Word Trees:
A word tree depicts multiple parallel sequences of words. It could be used to show which words most often follow or precede a target word (e.g., “Cats are…”) or to show a hierarchy of terms (e.g., a decision tree). Google word trees are able to process large amounts of text quickly.