Chat code like Jabber, Morpheus and Trillian, especially when it integrates with mobile signal devices like pagers and web phones, will likely be part of the healthy buying infrastructure to deliver the actual buying signal to the front end user of any Consumerium Services.
Alternatively, many messages regarding many products could be updated at once on some regular update schedule, which would remove the need for any dynamic or real-time update at the retail shelf, but which would run the risk of being sometimes a bit out of date. This is probably required anyway as it is slow to update messages via chat code, and could probably not be done within one second.
To expect any user to wait more than one second for a response, is probably a very poor assumption, especially for women with four children in a store at once (see Consumerium User Stories and worst cases for more on this).
Software requirements and protocol requirements will be affected by the chat code chosen. They may also be affected by the Wiki code chosen, as it is likely that different wikis will be well-integrated with different chat nets.