just looking at the first line of my yahoo cookie from BT
Y
v=1&n=fdv4pcpalqqrg&l=6h4o2em@1j8dj4hd4j.2ec/o&p=m21vvuk013000000&iz=
MEXX5DT&r=ia&lg=en-GB&intl=uk
yahoo.com/
notice the bit in red
MY POSTCODE!!!!!! (x'ed out 2 chars for privacy) 
easy for phorm to get my post code and match it to MY unique random number ID as when you logon to parental controls it will see the cookie go by along with its own
i also notice the reference to strings of numbers longer than 3 digits has gone from the webwise faq page
also notice 
http://routeplanner.rac.co.uk/showmulti.php?saddress=meXX%205dt&daddress=b69%206lt&vaddress1=&vaddress2=&vaddress  3=&vaddress4=&vaddress5=&rtype=fast&preferences=3&  trafficconditions=3&maptype=JAVA&nextgengeo=1
can pick up post code from travel sites when it passes data from one page to the next (my postcode above in red x'ed again), 
so no identifiable data???? pull the other one