"It's a shame when someone searching for pornographic material related to, say, llamas, is forced to slog though many pages of perfectly innocuous llama sites before finally hitting upon the llama porn he was looking for."
The unsafe search works by performing two Google queries, a normal query and a query with SafeSearch enabled. The set of "safe" results is then subtracted from the set of normal results to yield only "unsafe" entries.
One for your Bookmarks.
...or to add to your lf pulldown.