Naturally, I've joined :-) Why? Well, primarily because of the Party's opposition to the continuing demands of the communications industries to extend copyright far beyond what is sensible. I'm not interested in file-sharing, which is another issue.
When copyright was first established in the UK in the reign of Queen Anne it gave the creator of a work a monopoly to reproduce that work for 14 years. The notion being that this was a reasonable length of time in which the creator could be recompensed for the initial investment and derive some kind of subsequent income.
Now what do we have? As the Guardian report on the establishment of the Party noted:
Copyright for written works now stands at life plus 70 years, and copyright for sound recordings is 50 years after the recording is made, or 50 years after publication. The EU has extended copyright to 95 years for performers and sound recordings.
With the extension of copyright in this way, it is clear that it no longer protects the creator - it protects the publisher (of texts, of music, of recordings). The aim is not to provide the creator with a reward, but to prevent the wider distribution of texts, etc. and to limit the ability of future creators and performers to build readily upon the work of their predecessors. It is no longer possible to 'stand on the shoulders of giants' because the giants are the corporations and they are standing on you.
So - joint the Pirate Party and help to get some sense into the system.