Added the following introductory text: 

In of itself, the suite of OGSA Basic Security Profile 2.0 profiles is not sufficient to guarantee interoperability of all OGSA services.  The purpose

 of these profiles is to provide a flexible and extensible profiling of how secure communication requirements are advertised, discovered, and enacted.

  The specific secure communication requirements may vary between grid communities.  The intent is for a community to self-select such requirements 
that are appropriate and then leverage these profiles as necessary to achieve interoperability between its members (and/or cleanly discover where 
interoperability is not possible).