Look at this graph: http://www.alexa.com/siteinfo/voat.co It shot up to its current rank in almost no time. That is a lot faster growth than both reddit and HN experienced.
Of course it did; there was a big hullabaloo that led to some people migrating to it. That's not really a sign that they did anything right, or that they'll have similar momentum in the future.
The same thing happened to 8chan, and then it entered a gentle but consistent decline: http://www.alexa.com/siteinfo/8ch.net