On most forums I participate in, there is a way for me to see a list of my most recent posts/threads, and similarly there's usually a way for me to see a similar list for another user (this is particularly useful to me when I find someone's post/reply insightful and/or entertaining, and want to see what else (s)he's said recently)

Is there a feature like that here? If so, where can I find it? If not, WHY??? ;-)

Click on a person's Avatar. You will then be taken to their user profile.

A little bit underneath their avatar, you will then see a link called something like "See all messages written in the forums by XXX". Clicking on that will give you a complete list of all their posts, from most recent to least recent.