I think one of the most important points that is made in this article about Online Collaboration is the mention of an agreement. Having students collaborate online can be extremely helpful especially when you would like to cover other important material in class instead of dedicating it to group work. But the question is, when students collaborate online, how do you know that all of the group members are participating and contributing?
GoogleDocs are a helpful way to track who in the group is doing what. Every time a student makes a change to the document it will alert you as to who is making the change and what they have changed. Of course in order for that to be effective, the group must share their document with you.
However, there will always be that student who goes above and beyond to complete the assignment early and sometimes that involves taking on the brunt of the responsibility. This can be avoided by drafting an agreement between group members. The draft will include who will do what, and by what time. Hopefully this keeps the responsibility evenly distributed and on track. There is room for alterations within the agreement as well, but only if the whole group agrees to it.