It appears to me that mediation became an increasingly widespread means of dispute resolution, in the USA, from the beginnings in divorce cases to business disputes. In the late 70ies, mediation was imported to Germany where it is now practised by a rather small number of attorneys, only very few of whom are really trained. As a rule, with regard to the comparatively moderate legal fees, differences in procedural law, and the somewhat different education of judges, arbitrators, and attorneys who are very much inclined to suggest compromises, there appears to be only rather limited need to this additional means of dispute resolution.
Nonetheless, at least the techniques of mediation are increasingly applied in all kinds of disputes, ranging from town planning to collective bargaining, divorce cases, to child custody.
The DIS - Deutsche Institution für Schiedsgerichtswesen (German Institution of Arbitration), Cologne, initially established for the assistance in arbitral proceedings, now provides as well for assistance in and rules on mediation.
When drafting major contracts, I usually try to convince parties of the benefits of a multy step procedure of dispute resolution where arbitral procedure is made conditional on the failing of a preceding mediation procedure.