I thought perhaps to clarify --- I'm looking to tools that allow us an overlay on multiple contexts, without forcing us to go to yet a third place to track/log/transact, and which likewise aren't invasive of existing applications/content-contexts. The latter invasiveness requiring either heavy integration with the application, or being incorporated in the application from the ground up.
Further, as many groups I work with are using multiple tools/spaces to coordinate, it's hard to maintain an integrated view, yet acknowledgements and transactions that operate as an overlay would allow this.
This will depend upon two aspects: a transaction/identity/groupness server, and overlay-tools which allow us to operate and interact with the former from any context (like a wiki, or drupal site) or rather from many contexts not determined a priori. Currently I am exploring strategies to achieve this through Rich Internet Apps and Browser extensions.