Rival digital music stores are scrambling to get their responses to the UK launch of Amazon’s MP3 Store yesterday. We’ve already covered 7digital’s reaction, but now eMusic’s European MD Madeleine Milne has come out swinging too, pointing out that eMusic was “the first MP3 retailer to launch across Europe” back in September 2006.She also welcomes the Amazon launch, on account of it offering DRM-free MP3 files. Amazon will be stiff competition for eMusic though, on account of its deals with the major labels – something eMusic still lacks.However, Milne says eMusic will soon have one advantage over Amazon. “eMusic will shortly launch a next generation recommendation engine that uses a combination of human analysts and computer algorithms to help music fans find new music they love, in contrast to Amazon’s very traditional collaborative filtering method.”Intriguing stuff. Although the challenge for eMusic will be to prove that its new tech works better than Amazon’s – the ‘people who bought this, also bought that’ approach may be “very traditional”, but it’s a proven revenue generator.