We just added two easy ways to share a binder. You can now email a binder to some one else while you are viewing that binder. You can also easy tweet a binder from within the binder.
To see how this works, click on a binder to open it. Then click on one of the share icons in the lower right – either email or twitter – and send it off. You can try it out with this binder that Madelein created, a great collection of Power Point tutorials: