Based on a google site: search and an eyeball of the first couple of results pages I'd summarise as

www2 - partnering, alliances education [1] www3 - investor relations, careers [2] www4 - central european languages [3] www5 - japanese [4] www6 - no results found www7 - open vms [5] www8 - seems to be the primary site for english content

[1] https://www.google.co.uk/search?q=site%3Awww2.hp.com [2] https://www.google.co.uk/search?q=site%3Awww3.hp.com [3] https://www.google.co.uk/search?q=site%3Awww4.hp.com [4] https://www.google.co.uk/search?q=site%3Awww5.hp.com [5] https://www.google.co.uk/search?q=site%3Awww7.hp.com [6] https://www.google.co.uk/search?q=site%3Awww8.hp.com