It's easy to give edit rights to your friends in KeepandShare.

Shared documents with edit rights can be used for online sign up sheets. E.g., for Thanksgiving or any other major event with many players, create a document listing all the tasks and share it with the group and give them edit rights. Then ask them to edit the document and put their names and contributions next to the categories. They can even highlight their edits by selecting different text colors. It's just like passing a sign up sheet around in a meeting, but it's happening on line.