We have a funding experiment going on? I couldn't agree more with all of your criticisms of the current experiment. I know mk was excited to try it, but I literally haven't thought twice about it since the first day. I spoke with insomniasexx and she had the same feeling. Like dublinben, many users have been clamoring for a way to help support the site, which is really, really awesome. More and more, I like a straight up donation mechanism. You choose the amount. It's a good clean start, then we can go from there. I do like the barrier to entry that your suggestion brings though. That's a good thing.Similar to what kb suggested, to have an account, it costs two bucks. That's all. In fact, you can even have an account if you like for free, but to comment or post, you need to pay the two dollars.
There will be a transactional fixed cost of about $.30-$.40 just to process a $2 transaction. I have always liked the $5 model. It's clean, it covers the transactional cost and the cost per user and puts some more in the hubski hat for things like stickers, t-shirts etc.