I don't have a desk phone, so email was first option, nipping downstairs to visit them was the follow-up option. Face-to-face interaction wins the UX wars - although it can be a rarely available option.
It's cool, you can find the speed dial without looking and talk with people without using cpu cycles, internet bandwidth or battery. It also has this cultural vibe to it with people expecting you to get to the point, answer the query and terminate the connection.