Classifides needs a reply/message aspect

Right now if someone posts a classifieds ad there is no way for people to respond to the post. I want to avoid people from posting their email address. I'll like to keep all communication on the site. I'd like viewers of the ad to be able to send a private buddy press reply message to the user who posted the ad.

example post:

http://totalcaregivers.com/classified/care-for-my-grandparents/