The decision of who to include as a member in your ecosystem or network is a difficult one. We call this process bounding your network, as you are determining the boundaries of who you consider a member and who is not. The right answer depends largely on your objective and goals - what works for one community might not work for another. Consider what you want to learn, and who you would need to talk to in order to gain that insight and info. 

If you want someone included in your network maps later, they must be a member of your ecosystem before you start collecting data. For more info, read our best practices on Bounding your Network.