Reading this case study, I immediately had questions.
What type of queries were Trinh’s emails asking?
Was there something about her course design that made the need for so many emails inevitable?
Were her students globally less experienced using the Blackboard Learn LMS?
Had Trinh indicated how students should communicate with her?
Were there boundaries in place? Perhaps, by making herself available in so many ways to her students she had opened a ‘floodgate’ of 24/7 access to her?
I am not blaming Trinh for bringing the problem on herself. However, there may have been something she had done inadvertently to create/ allow the masses of emails to happen. Likewise, I would not want her students to see her make a ‘retreat’ from being available to them. However, there has to be an effective communication system or else, Trinh will eventually burn out from teaching the course.
Here are some solutions:

• Create a F.A.Q.’s page
• Allow students to help answer some queries through a specified discussion thread
• Create guidelines for when a personal email is most appropriate – of course, sensitive emails, assignment extension requests, etc. would have to go directly to Trinh. These guidelines would also include whether or not it would be appropriate to ask questions of Trinh in her blog or via Twitter.
• Within some grouping system, have peers check in with their group when situations/ problems arise that may be handled by the group
• Initiate ‘virtual’ office hours for a chance to get immediate responses to queries, these could be set a few times a week to guarantee that all time zones have an equal opportunity.