Ask HN: He submits the link 10 times, gets mega-upvoted on the 10th – Why?

The randomness of up-voting is pretty apparent on most sites user submitted content.

Note that the article has been submitted by 5 or 6 persons, not always the same user. Looking at the profiles and submission/comment history of the submitters, they look as different real users, not sockpuppets or something.