When you create your actions, you'll notice that your user account is listed as the creator of an action. If you've joined any groups, a sponsor dropdown box will be available as well.
You can choose to add a sponsor or remove yourself as the creator here. If you are listed as the creator, when activists take action you will get their information and they will be added to your account's email list. If a sponsor is listed, that group will get the data as well. If only a sponsor is listed, then only the group will get the data. Each action must have at least a sponsor or a creator, though you can have both if you'd like.
