It's a little hard to find for your own user; the only way I've found it to mangle the url to show me what others see when they click on my name, and then it's easy to find all threads from there.
I think it can be done by visiting your own profile and select posts, then select find all post by yourself (bottom of the page). Same options for topics you have started.
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.
Oh right. I don't get pop-up menus since I don't run scripts here. You can still do everything you need to be able to do, but something you need to go though some extra hoops, and I guess that's the case here.