This is stupid, and let me tell you why.
The biggest thing I'm scoffing at this "proposal" is the fact that you don't know what you're doing yet, and you're looking for possible ventures. To complicate matters, you want to include people from all over the world.
First, let me tell you that a successful business does not find members before coming up with an idea. Business opportunities are there to be seized. If you study the Fortune 500 companies, many of them were established due to a need the founder discovered or experienced. You don't search for opportunities, opportunities hit you in the face when you least expect it.
Second, there is the problem of where to incorporate a business. Will you do it in the US, or will you do it in a foreign country? What are the laws of the country you intend to do business with? Do they affect your revenues/operations at all? There are also citizenship/visa issues. For example, in the US, if you want to form an LLC/LLP (probably the best option for a private business), the managers (owners) must either be American citizen or have an US working visa. Remember, you can't just create a thread and offer services on Sythe and start making money, which leads to my third point.
What about taxes? How will you choose to be taxed, as a partnership or an LLC or something different? What tax laws/restrictions will you be under? Remember that (depending on country), if you deposit more than a certain amount of money into a bank account without reporting your income, the IRS or its international equivalent will come a-knocking. Trust me, they are not very pleasant people and are a bitch to deal with. I'm assuming here that you won't keep the money on PayPal forever.
In the USA, 50% of new startups fall under a year. Now, perhaps you have some great ideas that would obviously be counterproductive to reveal on a public forum, but I don't see it. The fact that you're trying to acquire members before deciding on a topic is very laughable. Also, I don't know why you'd want more people to join in; everyone knows that more members = more headaches/problems and less headaches. I'd suggest you wait until you learn what you're doing or start up a university degree before you attempt this endeavor. Also, I wouldn't be looking for partners through Sythe...
Source: 2nd year Harvard Business School student, and I am the CEO of a pretty successful startup