If you sell your iPod and don't remove your music first, you could find yourself with the Recording Industry Ass. of America (RIAA) breathing down your back. The organisation last week told sellers in the US that doing so is a clear violation of copyright law and warned them that it's sniffing out for infringers. Apple's rapid iPod refresh schedule, not to mention those of its competitors, have generated a tide of old music player offers in classified ads columns and on sites like eBay. Rather too many sellers are shipping their old machines with music libraries intact - some...