To be able to use the PM function you must have at least 200 posts. Please use a member's shoutbox/comments to communicate with the one-to-one. Also, please note using this is public.
To locate a member's shoutbox go to their profile (http://p.mobile9.com/username/ e.g. for me http://p.mobile9.com/adonisdemon/)
This is to help combat spam. We cannot monitor Spam if we cannot see it. By having the shoutbox facility we are in a better position to try and minimise the amount of unsolicited messages our members get. Once a member has 200 posts, unlikely to be a spammer, they can use the PM facility.
Note: Due to all-or-nothing a member with less than 200 posts cannot be PMed even if the sender has over 200 posts.