Legal
Bitcoin is subject to AML/KYC laws. This has caught out a lot of people in the UK. (e.g. http://bitcoinmagazine.com/interview-with-glbses-nefario/ )

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It's not formally recognised as a currency, but it is recognized as a virtual currency scheme (http://www.ecb.int/pub/pdf/other/virtualcurrencyschemes201210en.pdf) but that comes with very little legislation.