Finally found the answer in post 3806558 [webmasterworld.com]
It turns out that the numbers are from the search results urls from search.live.com - I guess it is just their way of encoding the search string.
Just goes to show the total lack of reality of MSN - what use is such a code in site analysis? - and how is one supposed to un-encode it? Geekism at its worst, and absolutely in line with Bill's policy of 'never state in plain English any fact that can be camouflaged with complicated obfuscation'! [this is best illustrated by the oxymoron, 'Windows Help']
[edited by: coopster at 12:15 pm (utc) on May 13, 2009] [edit reason] linked up reference [/edit]