ACTION-709: Write some examples for 2.5.3

Here's my proposal for a list of examples of out-of-scope means that may 
ascertain the users and servers preferences.


Current text:
The preferences of users and of servers MAY be ascertained by means 
outside the scope of this document.


Proposed text:
The preferences of users and of servers MAY be ascertained by means 
outside the scope of this document. These means include but are not 
limited to:
- the use by transforming proxies of a whitelist of Web sites for which 
content transformation is known to be useless and/or to break delivered 
content.
- the use by the transforming proxies of a blacklist of Web sites for 
which content transformation is known to be necessary.
- terms and conditions agreed upon between the user and the user's 
mobile carrier.



François.