I replied to this in the other thread. Coins paid and unpaid voting in our opinion shows financial backing for a coin. If you'll spending money voting for it you'll likely also provide services and care and feeding for the coin. It also seems to be a good indicator of potential volume. It does little for the bottom line honestly it does however pay for the costs in adding the coin.
What system would you propose? I don't think there is a best way, but I do feel this one provides a disincentive to keep building clone coins with no financial support.
John, this is one area where I disagree with you. I think the culture of accepting bribes to list coins is a really bad one that will not benefit the digital currency scene in the long run. It makes things look shady. If the NYSE held voting to determine which companies could be listed on their stock exchange, and they allowed votes to be "bought," how do you think that work turn out?
The vote buying system indeed encourage pump and dump coins because the devs, who have pre-mined a bunch of coin and want to unload it rapidly, will gladly pay some btc to get the coin listed knowing full well that they will receive a massive return on their vote/bribe investment by being able to dump their pre-mined coins quickly on a high-volume exchange.
I think a much better system would be to eliminate vote buying, and change the voting process so that you can vote ONE TIME ONLY in a voting cycle. The whole "vote x times an hour/day/etc is also very absurd and prone to abuse. It would be much simpler and fairer if each member could simply vote one single time in a voting cycle, then the exchange tallies up the votes at the end and lists the coin that won. Also, only members who have an account and have executed trades should be allowed to vote. Maybe there should be a minimum volume requirement as well (ie you have to have traded at least X btc worth of coins since opening your account) in order to vote. That would deter people from making accounts (and/or multiple accounts) solely to vote.