If I was responding to an ad, I would respect that and do all communications through email.
Most people responding say something along the lines of:
I’m interested. Please call me at xxx-xxxx
WTF?? If I wanted to talk on the phone I would have got you to call me.
Also, if you do respond to an ad, please sign your name. Nothing like getting an email from firstname.lastname@example.org and having no clue who I am talking to.