First, I 'm sorry if I misinterpreted the pling-system you are trying to implement. The initial info on your blog suggested this however. You’ve set up a rather complex system for rewarding the plings. I understand the necessity of it, but of course it lacks the transparency needed for everyone to understand.
I realise the uphill-battle you are facing to fight off the misuse of the existing pling-rewarding-system. And trying to make people pay for rewarding others is commendable. But in order to make this work you need a sizeable number of paying contributors. Otherwise allot of products will simply not get enough attention. Each pling-giver has its own idea what he likes, and thus rewards his favorites. This is not a problem if the group is large enough. The larger the number of pling-givers, the more evenly spread the plings will be. This is ultimately your end-goal, I presume.
I just fear you will never get that far. Why? Because the large majority of people visiting Open-desktop only do so a couple of times (correct me if I am wrong). Only some of them do the effort of voting up (or down) and even fewer leave a comment. Because most of them do not do the effort of registration. So, the majority of the users of our products are simply not available to act as quality-contributors.
In fact, those that do register, mostly have a vested interest in doing so. Because, usually they are the ones that upload a product. So you might end up in a situation where the contributors= product-uploaders . In other words: we judge ourselves. This incestual relation (sorry for the phrasing) is not going to get us any further in the idea of promoting quality in free software. Because we end up paying ourselves for our work.
I may exaggerate the situation a bit ( I do not have the statistics to back me up), and perhaps I’m to blunt about it. But I do genuinly care about this site. I’ve been a member since 2007 (as paulubuntu) so I am a big fan. I just want to make you aware of the consequences of your plans, so you can adjust whatever you would feel you need to do.
Addendum: You might want to re-read the last sentence of your last comment…