Interesting, but I wonder how commercial use of the API requires the license:
http://otlportal.stanford.edu/techfinder/technology/ID=24472
http://otlportal.stanford.edu/techfinder/technology/ID=24472
The tagger is licensed under the GNU General Public License (v2 or later).
The GPL, like other licenses meeting the 'open source definition', has no restrictions on use -- only on proprietary distribution under nonfree licenses.