You can leave comments on profiles, hotspots, shots and events - someone else's or your own. Go to the particular profile, hotspot, shot or event. On the bottom you will find a white box with the title "drop a line". Write your comment in the white box and hit "drop it" once you are done.

Go to "Mail" in the top navigation. Go into your "Inbox". On the left of each message you see a delete button. Once you hit that button your message will be deleted right away. A yellow layer to confirm this will appear that you can close.

Go to "Mail" on the top navigation. Choose "Inbox" from the drop down menu. You will get a list of your messages. Click on the blue subject to enter the message.

Go to mail on the top navigation. Click compose message in the drop down. You need to enter the person's correct username to send a message. Formulate your subject line and text. When you are done hit send. If you want to reply to a message that you received you can go to your inbox, go into the message you want to answer to and hit reply.