Eddie & John,
The posts that you make in the Visitor Message section is PUBLIC.
For the record, the GRAY or PURPLE colored REP squares are simply a designation that the giver of the POSITIVE REP is new to the forum and hasn't graduated to GREEN REP. Negative REP is almost always if not ALWAYS, RED.
I'm not sure if you can delete any of the Visitor messages or not.....It shows that you can edit them....
In summary, VISITOR MESSAGES are readable by anyone on the forum while PRIVATE MESSAGES are private between you and the party you are writing to and of course the FORUM OWNERS.
Best regards to the both of you.