Problem is if anyone has a great idea for a website he'll probably keep it for himself in hope he might realize it or at least sell it

Where are you from? If you're from a small country let's say in the EU you can try to start a dropshipping service for people who want to shop from UK online stores like ebay.co.uk for example or sportsdirect. This will be helped by the fact you'll bring this service through a website in your own language, so many non-English speakers who to this point have been unable to buy stuff from abroad will come to you. You need to make a store where you'll publish a selection of goods sold at sportsdirect and when somebody orders something from you you order it from sportsdirect to their address. You'll need to have credit/debit card payments on your site and charge them a bit more than the real cost so that you make profits.