Been watching this, obviously the testing etc shows that duplicate content can work to some degree, but realistically there is no meta description, underscores in the URLS and god knows what else wrong with the pages
Its clearly been slapped together and hats of for testing, and getting that type of traffic.
I highly doubt the site gets anywhere near 50k in visitors but it does rank for 20,000+ keywords all pretty much on page 2 and below hence why id love to see a screenshot of the analytics.
Obviously one line of text can be enough to rank for obscure keywords, and this site IMO opinion will end up being penalised for the duplicate content eventually.
Getting whatever traffic to this test website is great, but whether that is quality from organic search and rankings over the fact its being posted on popular forums opens up the debate as to where the traffic is coming from and what value there is in that traffic.
Would love to see more on the analytics side to see more about this traffic
"Confidence comes not from always being right but from not fearing to be wrong."