Google state that we can use a Google API key on our website applications, as long as it is not for Commercial use. What exactly do Google mean by this? I have a website where by I am providing a online free tool, for querying Google, for any one (Its purpose is irrelevant to this post). If I then start charging people to use my service at a later date, would that then constitute as Commercial use and put me in danger of losing my API Key?