You could always search your username since your name is in the post (b/c of the "Originally Posted by ___"), but if you did I guess every post with the word 'stuff' would turn up in the results. Still...tip for peeps with 'different' usernames, I guess.
A way to find out who has quoted you is to click on the ''Search'' button at the top of screen, then click on ''Advanced Search'' then type your username into the ''Key Word'' box in the top left of the screen, then select show results as posts instead of threads (it's threads by default) then click enter and it shows you the results of people who have quoted that username. For my name however because it's a general word that people use, I see some posts that aren't quoting me, but are just using the word nostalgia in general conversation.
Other than that you can just re-visit threads you've posted in to see if someone has replied to you, that's what I do sometimes.
But yeah, it would better if we had a simple notification feature.