Why does it matter? I'm tired of seeing people link other discussions. If it's a live active discussion, thats one thing, but a dead discussion from yesterday?....
The comments of a submission are valuable to those other than the participants. To readers that don't or won't comment, the concept of 'live active discussion' is moot. In fact, I could argue that it's most beneficial for a reader to wait until the comment activities die down.
Either way the link to another similar thread is an odd thing to be tired of.
D'oh! I searched "Yelp":last-24-hours before posting and your submission was right outside the threshold. My bad!
No worries, man. I think the comments are the most valuable part of posting. So actually my linking to a submission that yielded no comments was not valuable, but I guess it did lead another user to share a post that did have a discussion. Your submission had the right timing and sparked a discussion!