spica42 - 5:20 pm on Nov 1, 2012 (gmt 0)
The site in question is more than seven years old.
I found out (remembered) that I had started a test site two years back with tons of duplicate content for testing purposes.
I didn't configure the spider correctly so Google ended up crawling it. As there are lots of php errors on the site I, thought there is no way Google would give that site any authority. And to be sure, I even redirected all pages from the test site to the corresponding pages on my site in the end.
I found out today that that test site is actually ranking higher than our main site! To make things worse, there are also numerous other scalper sites that are ranking higher than my site too from phases on my site. WTF.
Why can't Google just use the date that it first index the content to determine which is the original source...? I don't understand but it's really disheartening.