Multiple different accounts were created and used to upvote his own stuff and target other users with downvotes. This is the second or third time a user has been banned for vote manipulation, and as far as I can remember, the only reason aside from spamming that a user has ever been banned. Please do not create alts for the sole purpose of giving yourself more internet points, it's pointless and we will be able to find out if it's happening.
In the future, we could implement account restrictions to try and curb this. Currently we have no restrictions on freshly created accounts, other than sub creation and captchas for posting. We could maybe add up/downvote restrictions based on age of account or account level.
But yeah, thought it would be best to make a note of the banning rather than explain what happened in a couple of weeks if someone asked where he went.
PS: No, the irony of making this post on an admin alt is not lost on me.
We've been evaluating that for a long time now and we're probably going to implement a few limitations. Maybe still allowing new users to downvote but making the downvotes ineffective until the user reaches a certain threshold?
Well, that's the most difficult part. We know votes are not a really effective way to sort content (mainly because it's too easy to manipulate) but we just haven't found a better way to do it while still preserving some ability for the users to collectively moderate the site.
Also, we never got to implement hiding posts that have too many downvotes. They might appear wayy down in the hot and top sorts but you'll still see them in the new sort (that's also why we added an option so sub mods can set the default sort for their subs, so that they can decide whether the content is moderated by voting or if just all content is visible)