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.
The same thing happened to 8chan, and then it entered a gentle but consistent decline: http://www.alexa.com/siteinfo/8ch.net
Actually the fact that they shot up at all is a sign they did something right.
Now it is a question whether they can maintain that momentum, but they did get a real good start.