The Pokes Instant Messaging is a site wide messaging/email service to communicate with other site users.  If you receive a message from another user, you will see this fact in the Pokes Instant Message box.  If you would like to send a message to another user, click on the number of messages in the Pokes Instant Messaging box, which will take you to the message form.  If you are using Internet Explorer, start to type in the user's name and you will see a drop down of matching users.  Unfortunately, right now, there is an issue with Firefox that is preventing that same function from working.  Be patient, the solution will be found.