I'm not sure what is meant by OpenCommerce. The first thing that came to my mind was interpreting the expression OpenCommerce as a complete sentence in the imperative. That would seem to entail taking commerce as one finds it, and opening it. The mental image of opening a can of worms comes to mind. What would one open? The books? The boardroom? What about the back door?
Given the seemingly business-friendly editorial position of MeatballWiki, I imagine it's more likely intended to mean creating commercial entities from the ground up, perhaps in a way that's less secretive than is customary. Depending on how much less secretive, this could be even more interesting than opening existing commerce.
Then there is the possibility of creating envitonments more open to commerce, such as what are called FreeTradeZones. This is exciting, but hardly revolutionary.
One interesting step toward opening commerce (in the "imperative" sense) would be making it easier to cross-reference product data from outside, ideally across entire industries. One example would be relating UPC's to NDB numbers. After all, everyone needs food, and the USDA's NDB opens up fairly detailed information about the nutritional composition of foodstuffs. There is a project called CueJack underway which seeks to put the power of UPC coding in the hands of consumers, although their stated interest seems to be more about counterbalancing PR than in counterbalancing InformationAsymmetry. Hopefully they will take a closer look at all the ways their technology could be used to OpenCommerce in tangible and useful ways.