Owl and privacy paragraph

As per the action I have taken over from Dan, I have written a few 
words on OWL and privacy (stating the obvious as it was put on the 
telecon).  This should show up in either Guide or Ref - I'll let the 
editors sort that out.  And, of course, editors should feel welcome 
to edit to suit.
  -JH


Privacy Issues

Any language offering an expressive semantics can be used to infer 
information that is not immediately expressed.  OWL is no exception, 
its ability to express ontological information about instances 
appearing in multiple documents, in particular, can allow the linking 
of data from diverse sources in a principled way.  In particular, the 
ability to express equivalences using owl:sameIndiviidualAs allows it 
to be stated that seemingly different individuals are actually the 
same.   Owl:InverseFunctionalProperty can also be used for the 
linking of individuals together.  For example, if it is stated that a 
property such as "SocialSecurityNumber" is an 
owl:InverseFunctionalProperty, then two separate individuals could be 
inferred to be identical based on having the same value of that 
property.  Further, when individuals are determined to be the same by 
one of these means, information about them in different sources can 
be merged, allowing information that was not directly represented in 
any one source to be determined. 

The ability of the Semantic Web to be used for linking information 
from multiple sources is a powerful feature that can be used in many 
applications [REFERENCE].  Combining this merging with the expressive 
power of OWL does, however, allow the potential for abuse and users 
should be aware of these privacy implications. 



[REFERENCE]
Hendler, James, Berners-Lee, Tim and Miller, Eric "Integrating 
Applications on the Semantic Web," Journal of the Institute of 
Electrical Engineers of Japan, Vol 122(10), October, 2002, p. 
676-680. available in English at http://www.w3.org/2002/07/swint
-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
http://www.cs.umd.edu/users/hendler