Everyone using this plugin should be very sure they've read Reuters/Calais Web Services' Terms of Service, particularly this bit:
You understand that Reuters will retain a copy of the metadata submitted by you or that generated by the Calais service. By submitting or generating metadata through the Calais service, you grant Reuters a non-exclusive perpetual, sublicensable, royalty-free license to that metadata.
Which means they can take the content you submit for tagging and use it as they see fit and/or sell it to someone else.
Always read the fine print.