I like the idea of a private scratch area for sharing larger bits of info, but I'd be concerned about potential DoS attacks the feature might introduce. If nodes are effectively invisible to all but the creator, what's to stop someone from creating a thousand scratch nodes with thousands of lines of junk each? Though this could happen now, there wouldn't be any checks that public nodes have. Some intelligent limits or quotas (e.g. 50k scratch space in 5 nodes per user) would likely curtail the problem.