Wired has a story about GoodMail, a service that charges the sender of emails and guarantees that they will get through the spam filters provided by ISPs. Amongst the services backing GoodMail are AOL and Yahoo.
With GoodMail, organisations pay US$0.0025 (i.e. a quarter cent) for each email. The amount has been designed to be affordable to senders, but a disincentive for spammers. About half the fees go to the ISP, the rest, presumably, to GoodMail. So the ISPs have an incentive to sign up to the GoodMail service.
Individuals and companies will still be allowed to send emails for free, but it is expected that there will be an increasing risk that ISPs' spam filters will block them – especially if the ISPs have a financial incentive to block free email.
It looks as though the days of free email are limited, with a cost implication for online access panels. However, a sample of 400 respondents might mean 2000 invitations, which would add US$5 to the total price, a price worth paying if it means that spam is reduced.