Glyn Moody writes: "Are there ever circumstances when software patents that require payment might be permitted by an open source licence? That's the question posed by a new licence that is being submitted to the Open Source Inititative (OSI) for review. The MPEG Working Group wants to release a reference implementation of the new MPEG eXtensible Middleware (MXM) standard as open source, but it also wants to be able to sell patent licences. If it can't, it might not make the implemention open source; but if it does, it might undermine the fight against software patent proliferation. So, what should be done?"