Let me expand on
@The Hat's answer a bit.
There are 4 ways to communicate directly to another forum member. Each of these will notify the other forum member you have posted something directly to them. I do not receive email notifications of this but see I have a response from someone when I log onto the forum as noted under the heading "Alert" in the top right of the page next to "Inbox" above my avatar.
The first two methods are to click on either "Quote" or "Reply" at the bottom right side of the other person's post you wish to comment on. This will incorporate all or some, respectively, of that person's post. You can also perform the same to functions by using your mouse cursor and left mouse button to highlight text in that person's post. When you let go of your left mouse button it brings up the two choices to either Quote or Reply. Choosing either will incorporate the desired text into a new post from you and alert the other person.
The third way is to use "@" in the body of your post. Just type "@" (without quotes) and when you have typed at least 3 characters that are the beginning of the other forum member's name it will pop up a small window with all members whose name begins with those first three characters. Choose the member from that list or continue to type more of the person's name, or all of it if you like, to narrow the search. The member will be notified you have posted something at them.
The fourth way is to private message them. This function is called a "Conversation" and can be accessed through the "Inbox" heading I mention before above your avatar on the top right of your screen next to "Alerts". You can include one of more people to message with privately. These do not show up on the forum for everyone to read.
Maybe there are other ways. Let us know! We can all learn from each other.
PS -- If you click on The Hat's "Location" in his avatar (Wicklow, Ireland) it will take you to Google maps and there is a picture of his bungalow.