It hasn't helped me very much. It is a wonderful book, but I do not think I would try sending it via eletronic mail unless it was encoded and copywrited. Unless you receive a notice from the e-mail carrier that it didn't go thru, you have no real, firm idea that the person you sent it to actually received it. RSVP is becoming more common than you might realize. Diane Rhodes Amarillo, TX Electronic queries and submissions have been a real godsend for me, a very efficient way of communicating and meeting deadlines.
Response time varies by editors.
And each has they own style. Other answer in more detail. Over all, email and the Internet has enhanced my freelance business, especially since I live in a rural community. Sheryl Rodgers Blanco, TX Electronic queries and submission seem to have the most value in cases where you have already established a working relationship with an editor. It seems to be much easier to ignore electronic communications from strangers.