Notify their host and tell them that they don't comply with reported DMCA notices. If they don't do anything sue them too.
http://whois.domaintools.com/hotfile.com
http://whois.domaintools.com/sharingmatrix.com
http://www.webzilla.nl/
http://www.webzilla.nl/about/aup.html
http://www.copyright.gov/onlinesp/ag...lemuricomm.pdf (contact info for hotfile's host)
You can also contact Moniker (they provide the domain whois privacy for sharingmatrix) and demand to get their real contact info, allthough they maybe don't care without a court order.
http://www.moniker.com/help/dtc.jsp (See 22. DOMAIN WHOIS PRIVACY )
They're definately a pain in the ass. Rapidshare & co too, of course, but at least they take down the stuff immediately.
Good Luck & Keep us posted