It usually goes something like this. Entrepreneur can't wait to tell you about his idea that wil "literally" change the world. It's the biggest thing since the big bang and he can't wait to get started on it and start raking in the combined GNP of all the countries on earth combined. The idea is so big you just HAVE to sign an NDA because if you didn't you would for sure steal it because it's so great.
So you sign the NDA.
Then you get the pitch: it's a website called myfreediscussionsite.biz where people can go and have discussion with each other on any topic. No, it's not just a forum because you only see discussions and profile of people you are friends with. Also, you can post status updates about what you're doing and people can comment on them or give them a thumbs up. No, it's not like Facebook because this one has a red theme instead of a blue theme. Also, Google is really successful so myfreediscussionsite.biz.co.uk also has a search engine where you can search for other discussions taking place on the internet and you can post on those discussions and invite people to continue them on myfreediscussionsite.org.co.uk.net.
Once users begin using the site, users are charged a small fee for each post - just a few cents. Facebook has a billion users, and the entrepreneur is sure that we can take at least half of them away to our new service within the first month. Also, pinterest and instagram are pretty cool so you will be able to pin things from around the web and add hipster filters to them. There's something that resembles twitter in there as well, but it's better because it gives you 150 characters instead of 140 and is therefore better. The best part is you don't have to do any of the design because the entrepreneurs buddy has a son who is a "design whiz" and even got the web design merit badge in boy scouts.
Also, the guy doesn't really have any money NOW to pay you, but you'll totally own a piece of the company and you'll get a a fleet of gold-plated Ferraris as soon as they go public which will be in under 18 months for sure, unless they get purchased first for ten trillionz(tm) of dollars by god almighty himself.