Imagine a tax system for IP modeled on real estate property taxes. To retain a patent, you would pay a tax based on assessed value. You could sell the patent,

Imagine a tax system for IP modeled on real estate property taxes. To retain a patent, you would pay a tax based on assessed value. You could sell the patent, or enter it into the public domain. Failure to pay would result in forfeiture of the patent (ie. sold at auction, or entering into the public domain). This could create a self-funding process for patent regulation and monitoring, and a check against unhealthy patent proliferation. It would discourage patent trolls from sitting on patents, large companies from accumulating a "war chest" of patents, and encourage FRAND licensing.