Ethnographic research can take place wherever your customers interact with your product or service - in their homes, at their offices or in stores, for example.
This research generally uses a one-on-one interview combined with careful observation.
Ethnographic interviews are useful when the environment plays an important role in the usage or purchase of a product or service.
These interviews often reveal telling details respondents cannot remember in a more "sterile" setting (such as a focus group).
Observing respondents interacting with a product or service in its usage or purchase environment often demonstrates that users subconciously apply specific "mental models" or rules of thumb - which they themselves may be unaware of.