Why no one could had copycatted PlentyOfFish (POF)?

Markus Frind, in a recent post, has explained PlentyOfFish's revenue by Google Adsense during 2003 - 2006.
He had not said a word about revenue from Yahoo (PlentyOfFish failed to receive revenue by Yahoo)
http://plentyoffish.wordpress.com/2014/05/12/adsense-breakdown/


http://plentyoffish.wordpress.com/2007/02/28/eharmony-operational-details/

eHarmony had been copycatted several times in many countries.
http://onlinedatingsoundbarrier.blogspot.com.ar/2012/03/over-16-similarities-between-eharmony.html
But why no one could had copycatted PlentyOfFish (POF)?
All the ones who tried to replicate PlentyOfFish (POF) failed. They lost lots amounts of money, like:
CitasWeb
Pachetes
AlquienAQuienQuerer and others.
http://onlinedatingsoundbarrier.blogspot.com.ar/2011/01/3-big-south-american-failed-proposals.html
http://onlinedatingsoundbarrier.blogspot.com.ar/2010/10/amorenlinea-oasisactive.html
http://onlinedatingsoundbarrier.blogspot.com.ar/2011/12/free-model-is-dead.html

Or OkCupid or Zoosk
 http://onlinedatingsoundbarrier.blogspot.com.ar/2014/05/zoosk-inc-25-pages-report.html

The explanation is quite simple.
PlentyOfFish (POF) used to have a direct link to AdultFriendFinder, to receive commissions when prospective daters sent to AdultFriendFinder from PlentyOfFish (POF)  acquired a paid membership.
PlentyOfFish (POF) used to have a direct link to eHarmony, to receive commissions when prospective daters sent to eHarmony from PlentyOfFish (POF)  acquired a paid membership.

PlentyOfFish (POF) continually needs to buy traffic.
The main secret of PlentyOfFish is: they buy expensive traffic and sell it cheaper, thanks to that it can display ads of paid online dating sites and receive commissions paid from them. PlentyOfFish Media also owns several white label dating sites for that purpose.
To send tired daters from free sites to paid online dating sites.
PlentyOfFish (POF) needs to show ads mainly from online paid sites, then send prospective customers there and receive commissions when they acquire a paid membership.
A new Legislation to rule online dating sites, can hurt free/freemium sites like PlentyOfFish.
http://onlinedatingsoundbarrier.blogspot.com.ar/2014/02/too-late-and-unnecessary-part-2.html
http://onlinedatingsoundbarrier.blogspot.com.ar/2014/01/will-plentyoffish-collapse-this-2014.html


With 10 billion a month pageviews, I estimate PlentyOfFish (POF) revenue in the range of USD 50 million (2014)
but
PlentyOfFish has the traffic, others receive the money. 
http://onlinedatingsoundbarrier.blogspot.com.ar/2014/04/my-answer-to-topeka-analysis-why.html
http://myip.ms/info/whois/199.182.216.166/k/349709544/website/www.pof.com
http://onlinedatingsoundbarrier.blogspot.com.ar/2013/06/the-main-secret-of-plentyoffish-pof.html
http://plentyoffish.wordpress.com/2009/09/24/worlds-top-dating-sites-for-august-from-comscore/
http://www.onlinepersonalswatch.com/news/2009/09/worlds-top-dating-sites.html#comments