After studying Marketing in business school I decided I wanted to move from France, mostly because I wanted to speak English. Almost 4 years later I'm in Ireland and still like English and this is why I joined Freelancer.
Living in Ireland, working for a large video games group and doing crossword puzzles allowed me to develop my vocabulary extensively and to reach a high fluency level in English.
As for why I think translation is crucial for a business, I think that offering a great product or service might not be enough if you can't manage to explain to your customers how great it is in their language. Too many times I have seen typos or syntax errors bring down the level of a translation and make it sound unprofessional, or even amateur. Don't make that mistake :)