The first paid proposal (March 2009) was the "Serious Member Badge". Prospective customers should had passed a Sincerity and Integrity Test before they were allowed to acquire that proposal. It performed as a virtual gift for yourself, a virtual gold medal saying “Serious Member”.
The second and actual paid proposal (August 2011) is different from the first one. It includes a "home grown" compatibility matching system called UltraMatch; a Behavioural Recommendation Engine.
That exclusive feature is only available to users with an upgraded membership, who could discover their most compatible matches on PlentyOfFish.
As one PlentyOfFish member had said in the forums "we don't even know what's in the "regular matches" formula (beyond age/height/child status/smoking/distance variables) much less the "Ultra Matches" formula to know if PAYING to upgrade to "Ultra Matches" is even worth it."
The effectiveness/efficiency level of Behavioural Matching Algorithms are less than 10%!!!
They cannot break ...... The Online Dating Sound Barrier.