There are a number of ways your privacy can be compromised under this form of counseling. The most likely way is for someone else to see your correspondence, either by using your computer or by reading something that you print. Or your correspondence might be seen if you write from a computer at work.
Some employers regularly monitor e-mail correspondence.
I do not recommend that you write from your place of work. I will keep our correspondence secure on my own personal computer. If you plan to contact me again, and request it, I will keep your correspondence in a computer file with a password code. I may keep examples from individual letters, minus any identifiable information for my own use in future data collection. We have all heard of the possibility of our e-mail correspondence being stolen over the Internet, but this is a highly unlikely scenario.