It certainly could be made. Not my style, but interesting concept. Perhaps if you are interested enough, it will be something that will encourage you to learn to make plugins. It seems like a good simple thing to start with, and the best way to learn is to make something you actually want for yourself.
If I were doing it I might find a way to collect topics discussed in recent days, build a parser to cut and paste phrases from Topic Tables, then set up the trigger words to call the function.
