Negotiation may be thought of as "communications for agreement."
Hence, mediation is "assisted communications for agreement."
Central to mediation is the concept of "informed consent." So long as participants understand the nature of a contemplated mediation process and effectively consent to participate in the described process, virtually any mediation process is possible and appropriate.
Key Qualities of the Mediation Process
Voluntary - You can leave at any time for any reason, or no reason.
Collaborative - You are encouraged to work together to solve your problem(s) and to reach what you perceive to be your best agreement.
Controlled - You have complete decision-making power and a veto over each and every provision of any mediated agreement. Nothing can be imposed on you.
Confidential - Mediation is confidential, to the extent you desire and agree, be that by statute, contract, rules of evidence or privilege. Mediation discussions and all materials developed for a mediation are not admissible in any subsequent court or other contested proceeding, except for a finalized and signed mediated agreement. Your mediator is obligated to describe any exceptions to this general confidentiality of mediation. Confidentiality in mediation may be waived in writing, although the mediator may retain his or her own ability to refuse to testify in any contested case. The extent of confidentiality for any "caucus meetings" (meetings between the mediator and individual parties) should also be defined.
Informed - The mediation process offers a full opportunity to obtain and incorporate legal and other expert information and advice. Mutually acceptable experts can be retained. Such jointly obtained expert information can be designated as either confidential to the mediation or, as the parties desire, as admissible in any subsequent contested proceeding. Expert advice is never determinative in mediation. The parties always retain decision-making power. Mediators are bound to encourage parties to obtain legal counsel and to advise them to have any mediated agreement involving legal issues reviewed by independent legal counsel prior to signing. Whether legal advice is sought is, ultimately, a decision of each mediation participant.
Impartial, Neutral, Balanced and Safe - The mediator has an equal and balanced responsibility to assist each mediating party and cannot favor the interests of any one party over another, nor should the mediator favor a particular result in the mediation. Your mediator is ethically obligated to acknowledge any substantive bias on substantive issues in discussion. The mediator's role is to ensure that parties reach agreements in a voluntarily and informed manner, and not as a result of coercion or intimidation.
Self-Responsible and Satisfying - Based upon having actively resolved your own conflict, participant satisfaction, likelihood of compliance and self-esteem are found by research to be dramatically elevated through mediation.
Here is an interesting review of the Internets attempts to define mediation.