Although this is a good idea, I think it'd be easier to use use node id's when linking to replies. It WOULD be nice if a square-bracket link could point to a node id, like this:
That'd be just as convenient for linking, and you wouldn't have to go back and change all your titles.
Update: kudra has made some updated suggestions on her home node, since root level nodes can't be edited (hint, hint).
After discussing it a little more with kudra, I find I misunderstood her intent; She's not proposing we all go back and change titles on existing nodes, she's suggesting we should change node titles on replies. She has a good point with that; I agree completely. To prove it, I'm going to change the title of this reply. <G>