I guess this must be a pretty empowering concept to some people. Take those nasty spammers who fill your inbox with "Ch3ap V1c0d1n!!!!" and "FREE Credit Rating Analysis!" and tell them that if they want to make their way into your Gmail, they're going to have to pay the toll. Kind of like that troll-under-the-bridge fairy tale--or was that a Monty Python sketch?
I digress. There are a few companies out there that are trying to convince you that opting into spam is not only good, it can get you some pocket change (InboxDollars comes to mind). But as far as we know, a new company called Boxbe--which we heard about in the San Jose Mercury News--is the first to give it the troll-under-the-bridge spin. Interested customers sign up for a Boxbe.com e-mail forwarding account. You can set it so that only certain e-mail addresses can contact you (i.e. your friends) and name a fee that a marketer will be required to fork over to you in order for one of its e-mails to get through. Then, ideally, you accumulate a small fortune. (Or not.)
The big catch is that Boxbe isn't actually a spam filter. It doesn't do anything for spam that may be coming into your regular e-mail account, just the mail that is going to your Boxbe forwarding address. So if you already have a spam problem, this doesn't look like it'll be an ample solution. The ideal Boxbe customer is, at least in my opinion, a novice Internet user who's just starting to use services that require e-mail registration. By plugging a Boxbe address into a social networking site or e-mail list, you can guarantee (according to the company) that you won't be getting spam from it other than the stuff that you're demanding cash for. But as for pre-existing spam, nada.
And there's another big downside. If your friends are sending e-mails to a Boxbe.com e-mail address, they'll sort of be able to catch onto the fact that you're trying to squeeze money out of poor, innocent spammers.