once you uploaded something you got a link with a unique ID which you could share. Other people could not access your file without knowledge of this unique link

once you uploaded something you got a link with a unique ID which you could share. Other people could not access your file without knowledge of this unique link as you could not search for specific files (unlike Youtube). As far as I know there was also a list of Top Downloaded files but those didn't resemble the truth as they were carefully selected by Megaupload (to make sure that only legal content would be listed)