I know forum software suggestions are usually ignored, but I’m curious to know if it’s even an option with newer versions of the board software to do something similar to how @username works on Twitter - some bbcode function that would note (and be searchable and notify) when either a user’s post is quoted, or their username is otherwise mentioned.
That’d be awesome, but I wonder how it’d work for users with spaces in their names, or if that breaks it’s functionality.
Not an option in what we have now. At the present time there is no upgrade planned, we’ll let you know if there is.
And actually no, suggestions are not “ignored.” Most often, as in this case, what you ask for is not available.
Suggestions are rarely ignored. Usually one of TPTB has the courtesy to come into a thread and tell us the suggestions won’t be implemented, but that isn’t the same as being ignored.
Distinction noted. 
There is a Greasemonkey (Firefox)/Chrome script that will at least tell you when someone quotes you.
And there is always Google, where you can search for your username on this site alone as well as restrict the results to only in a certain amount of days.
Knowing that the search engine here often balks on simple phrases, it might be best to leave this sort of thing to Google.
I didn’t know about the Greasemonkey script. Where is that? Is there some general resource page for SDMB hacks?
I was thinking less of a vanity search, and more along the lines of turning that thing people do when they start a post by addressing another user with their name in bold, into an actual function.
Oh, sorry. I don’t have it anymore–it runs a bit too slow on my computer for my tastes. And it’s not coming up in a simple search. Hopefully someone else can tell you. It was weirdaaron’s script that also allowed hovering over picture links and other improvements. And, if someone finds it, I can modify it and remove the other functions if you’d like.
As far as I know, there is no repository of scripts for the SDMB, though that’s a good idea, really.
And I’m not sure how this feature would work unless it does a vanity search. Just checking quotes is possible, but figuring out the difference between whether someone is talking to you or just referencing your name is not something I can think of a way to do.
I could see putting in a button that automatically did that vanity search. Though, with The Powers That Be’s reluctance to change anything, you might be better off asking for a Greasemonkey/Chrome script.
A vanity search can be done very easily. Go to Advanced Search, search by Username.