Although still accounting for a small segment of the global carbon market, the voluntary carbon market is a place for innovation where original solutions are proposed to deal with some challenges faced by the regulatory market, including efforts to value the occasional ancillary benefits of climate action, to simplify methodologies, or to guarantee the permanence of forestry assets. These innovations are reflected in the different standards used for voluntary offset projects and may provide some valuable lessons for on-going post-2012 negotiations. This study analyses two aspects of these standards: the type of projects they attract, and the transaction costs entailed by their procedures.