Firstly, I sincerely doubt it's an original idea - the problem with so many millions of people out there is that they tend to have similar ideas. Obviously they do come along from time to time, but I reckon there's millions of non-original ideas for every good one. Secondly, you're effectively creating software, and only the source code can really be copyrighted. Your only real saving grace will be to do the job so well first time round that nobody else can do it better (eg. ebay, friendsreunited, lastminute, etc.) - however, do you also know that the site is technologically feasible? I'm happy to enter an NDA to give you further advice (since I couldn't work on it now even if I wanted to), but as I say, there's not really a whole bunch you can do to protect it except to go to market fast, and with a good enough product that the consumer will only come to you.