In a followup to his Privacy, Accuracy, Security: Pick Two post, outlining some of the inherent problems of "compulsory licensing" schemes, Aaron Swartz outlines a decentralized way to allocate compulsory levies to creators, based on digital cash.
LawMeme calls this a "Proto Whuffie", after the reputation-currency in a Cory Doctorow novel, but since this involves real cash, it's actually more like the sorts of voucher systems often proposed (and sometimes implemented) when policymakers believe that too little consumption of a particular class of goods would occur otherwise, but they still want to leave production of the goods and allication of the expenditures to the individual decisions of private actors.
Examples include food stamps -- to boost consumption of food, both for the benefit of the poor and for food businesses (the US Dept. orf Agriculture, not the Department of Welfare, administers the food stamp program) -- and school tuition vouchers -- to boost spending on youth education above what parents in a private education market might spend. The general approach has sometimes been denigrated as "voucher socialism," especially in the context of debates over school vouchers among economic libertarians, but in most cases, a voucherized market should be better than command-and-control socialism, where a small group of bureaucrats allocate (or set the politically-gamed formulas for allocation) of involuntary payments.
In the creative compensation/compulsory licensing sphere, this proposal could work out to "compulsory payment but voluntary allocation," and would form the least objectionable "compulsory licensing" scheme of all I've seen proposed.
In particular, it could reduce the chances that cartels of those who are already well mobbed-up with the federal government (copyright, broadcast, telecom, and government-contracting giants) could rig the whole system for their own eternal enrichment, small creators be damned.
Vouchers could also minimize, but not eliminate, the possibility that a compulsory license fees would be denied to controversial forms of art, like disfavored political viewpoints and "obscene" material (eg "nazi pornography").
There remain the problems of all voucher systems: some people will pretend to be of the recipient class -- in this case creators -- to be able to collect and convert vouchers to cash. Even among "true" creators, a de facto exchange rate between vouchers and cash will emerge, at which a person can reliably "sell" their vouchers, rather than giving them as a reward for creative output. But I know I'd prefer these problems to a system of total monitoring and bureaucratic, formulaic allocation, and perhaps compulsory proponents would prefer these problems to not having compelled payment for digital art at all.