12. The system of claim 10 , wherein the operations further comprise: establishing a hierarchy of delegation authority for the signatories to the collaborative email document; establishing at least one authority delegation policy comprising at least one rule for automated delegation of signature authority among the signatories in the hierarchy; and delegating the signature authority from at least one signatory to another signatory in accordance with the at least one authority delegation policy.
12. The system of claim 10 , wherein the operations further comprise: establishing a hierarchy of delegation authority for the signatories to the collaborative email document; establishing at least one authority delegation policy comprising at least one rule for automated delegation of signature authority among the signatories in the hierarchy; and delegating the signature authority from at least one signatory to another signatory in accordance with the at least one authority delegation policy. 13. The system of claim 12 , wherein rules for an automated delegation of signature authority comprise: a first rule that the signature authority of a first signatory having a first position in a hierarchy of delegation authority may be delegated to a second signatory having a second position in the hierarchy of delegation authority, wherein the second position is higher in the hierarchy than the first position; a second rule that a first signatory having a first position in the hierarchy of delegation authority may digitally sign the collaborative email document only after a second signatory having a second position in the hierarchy of delegation authority has signed the collaborative email document, wherein the second position is higher in the hierarchy than the first position; a third rule that the signature authority is to be delegated to a second signatory if the first signatory does not sign the collaborative email document within a specified period of time; and a fourth rule that the signature authority may be delegated during a specified period of time.