Tannen writes from the perspective that there are key, quantifiable differences in men's and women's speech from a sociolinguistic perspective which can be applied to workplace communication.  Although this book was written for a general non-academic audience, it can offer some interesting theories of spoken language and gender and power in an office environment, which arguably could be extended to email or electronic communications on the job.  Chapter 2 deals with conversational rituals that take place on the job: routines such as apologizing, giving criticism, ritual fighting, compliments, and complaints.  Chapter 2 discusses "Indirectness at Work" and how indirect speech can be viewed as both powerless and powerful depending upon the gender of the speakers and listeners.  In my experience, such rituals and directness/indirectness are key features in gendered speech found both in real-time verbal speech and in written internet venues.