Do you see a posting that you would like to comment on, but want to do it privately to the author?
Do you see someone near where you live and wish to contact them?
Do you wish to ask someone for assistance privately?
Well, at the bottom of every post, and long side every name in the Member list, is a "PM" button. You can click that button to compose and send a private message to the person.
If you have private messages waiting, you will either get an email notification if your profile is set that way, or you will see an indication that you have messages in the header (top) of nearly every page.
Thanks!