I can't find that on my profile page (reached by clicking my name towards the top right of page; left of 'inbox' and 'alerts'). But I noticed I could see my profile as others see it if I click on my name after posting, just as I could garrets and others, and from there I can simply select to view all threads. But if you don't post often and can't remember somewhere you last posted (and nobody liked it, so you didn't get an alert to it), then it's difficult.