The regular 50 minute hour appointments in an office make a firm psychotherapeutic boundary. Using email, such a shared time does not happen, you write about your feelings in your own time. You can do it in long or short bursts. You can send or *not send* what you have written. You can edit. The time and place you do this in is your psychotherapy space, a virtual shared space.
Structure around time does exist online and assists the therapy. One boundary is that I write for a maximum of one hour in one sitting, even if there is material in the email you sent that I have not worked with. If this happens I will discuss it in my response. My fee is associated with the time I spend working with you. The balance in your account defines a base-line which we both understand. We can bring more awareness and structure to this by discussing the length and frequency of our correspondence.
In all psychotherapy there develops a relationship which is independent of the actual meeting times. Psychotherapy has often been likened to a conversation. Online therapy enhances this aspect of the therapy relationship. It is further fostered by rapid short exchanges in addition to longer emails. I do not bill for emails that take less than 5 minutes.
More about working with longer emails