I'm a Web developper and have a dating website idea.
I'll meet in the next few weeks some webmarketers that could be my potential partners.
I'll talk about the idea of course and make them an interactive demo.
Should I make them sign a NDA knowing that the website is technically easy to setup ?
Stop worrying and starting building. But only after you've talked to your customers to ensure you're building something they want and will use.
Only if there is something on your website that had not be invented yet by the other 2000000,0000 dating websites out there :)