Just because your group is separated by miles, states, or even oceans doesn't mean you can't help get the collaborative ball rolling. But how? The first thing is to learn the personalities and behavior of your team members. This can actually be difficult, especially if you're working with people you don't know. In the real world, it can be easy to tell if someone is a natural leader or someone is a note-taker, but online, it can be difficult. The hope, of course, is that a normally shy person will take to onilne collaboration and will speak up more, but then you might have someone who would normally be a leader in the real world hanging back online or not talking at all.
This could be for a number of reasons--perhaps the shy person enjoys technology and now has a reason to utilize it; maybe the natural leader hasn't used technology that much as he is a bit distrustful of it. How do you combat this?
First, make sure that everyone knows that their opinions and views are important. Different people can create ideas, but these people may also dismiss an idea if it goes against what they believe. Allow people to express their views, while also allowing people to add to that viewpoint or to offer up a difference of opinion. It's very important that group members know that everyone is to be respected, even if their idea or method differs from theirs.
Secondly, make sure that all involved know their roles and what the end goal is for those roles and the project at hand. If possible, allow each member to have a day or week in which everyone is focused on that person's role or part of the project. This allows for everyone to be in the spotlight, without feeling as though their ideas aren't being heard.
Third, make sure everyone knows that, should they need help, help is available for them. Let group members know they can get help from each other and that they are also willing to give help. For instance, let's say that the natural leader is a bit afraid of using online collaboration tools or the computer itself. This could allow the shy guy or gal to offer up their assistance to help them learn. The natural leader could then provide suggestions for the shy guy to feel more confident when not behind a computer screen.