I'm just reading up on it now. From what I can tell, it's a secure way to anonymously store and retrieve data. I am in absolutely no way sure of that, but what I'm initially seeing is saying that. As to your question: You need to download the client from that link to use it. I'm going to do some more reading before I decide if I want it anywhere near my PC. I'm erring on the side of being vigilant against backdoors and other fun stuff. If it's legit, it'll end up here eventually.