Larry Seltzer posts an opinion that rate-limiting, or capping the number of emails a consumer account can send, should be used in the war on spam. Its appealing because cutting it off at the source would in theory effect only 1% of users and it does raise costs for Senders.
I think the time has come to be more specific. Set a rate limit for outbound mail for consumer accounts. There are systems available to enforce it. And it would be yet another sign to users whose computers have been taken over that they need to clean them out.
Like any solution to spam there are tradeoffs. But this prohibition could have the effect of handing a drunk a shotgun with instructions to plug a hole in a leaking dyke with it. There is a better mixed metaphor, but you'll get my point.
Senders will arbitrage by setting up more accounts to acheive current volumes. This will increase marginal costs for senders, but the marginal cost for managing whole new accounts would be greater. Also, this new form of email jail would be arbitraged by service providers as the disaffected 1% would be seeking alternatives, when say, their bulk mailing for the yearly event they produce is capped. Add to this a new cost for rating and how it goes against stupid network principles.
Spam is an economic problem, we don't have models that account for all incentives and this is just the opinion of one Spamonomist. In general, this is a form of price-fixing that may have negative externalities.
