I'm planning to start up an online community network of foreign investors, giving them access to investment information and to the opportunity of contacting the other members of the network in order to do business together.
To build an online community you need to show your expertise and leadership in the subject. You can start by blogging content in the subject and start attracting interested people in the subject. It is a rule that the number of people that reads is 3 to 5 times the number of people that collaborate in the site. You break this rule by having more and more people involved in the discussions and when you have great quality producers of content sharing ideas and answering questions you are on track to grow the community.
From the investment side, it is a very complex issue because this subject the people needs a higher level of trust of the people they are taking. I foresight a great challenge in sharing information about deals, then I will find how the share the learning of the subject as a way to gain trust.