The answer that appears in the Site Orientation and FAQ section is by manu08 and dates to May 2007.
Up at the top left of the page, where it says "Logged in as manu08", click on your name. That takes you to your profile. On the left, the third item down is "Options", with a drop down box. Click that arrow, and then click on "View all posts". That gives you every post you've ever made. Also, you can click "View all threads", to show the threads you've started.
Is it still correct or does it need updating? I can't find "Logged in as myname". How do I get to my profile?