I heard that there were gonna be two announcements from Kojima at E3.
If thats the case then Raiden might mean MGS4 for 360, and Big Boss might mean a MGS5 announcement.
MGS4 will have its "S" subtitle hence the "s" on the site, and MGS5 could be from the "S" being interpreted as a "5" or vice versa.
Just my thoughts.







