Google has a new auto complete thing - only it shows you webpages as you type. It also has a "blacklist" of words where it won't show you the webpages as you type.
Spank is one of them. Seriously, we are up there with some very disturbing stuff (things like 2g1c and acrotomophilia).
For a list of things that google has equated to "spank", see
http://www.2600.com/googleblacklist/Goodgulf