Many OP on Chowhound will ask "Where Can I Find a Phiily Cheesesteak" or "Help me find Great Texas BBQ" or "Looking for the Best Xiao Long Bao" or something similar.
My personal guideline for replying is as follows:
1) Best as I can, determine what makes up the essential characteristics of said item.
2) Think if I know of an example that fits the criteria
3) Have I had it and find it terrific?
If I reply, I will always keep in mind the three points above. This way, my reply is honest, answers the request, and does not waste time sending someone on a wild goose chase.
For example, if someone from Philly is looking for a Philly Cheesesteak, I wiill first determine that it should be on a roll that is a hoagie roll, not 'supermarket bread' that they grill the beef, and that they have grilled onions available. Furthermore, the place will not add extra toppings without asking or warning me first.
If I can think of an example that fits my three points above, I will recommend it. If I can't think of a place, I might respond with a caveat: "but the bread is nothing special", or "I've never been to Philly, but.... "
I am against the idea of responding if I don't bother to find out what they are talking about, or I will respond with a caveat.
I do not put people down for chasing after their long-sought request. If I can find a restaurant with one item I can enthusiastically recommend, I will do so, but I will clarify that. "Looking for authentic Sichuan?" I might respond with "Go here for the Ma Po Tofu, but the rest of the stuff is just average."
Sometimes I will see the broad request "Looking for Authentic Chinese?" In which case I might ask for further clarification, or just go ahead and list my top three and explain the style.
Looking for NY style Chinese-American? That's fine too, I will probably have a suggestion.
Looking for St Louis pizza? Sorry, but I have never been to St Louis, I don't really understand what that means, and it's highly doubtful I will respond even if you explain it to me, unless I am the only one who knows of a place called 'St Louis Pizza', and even then I would tell people to call first.
So there you have it. It's not complicated, no fuss. I try to avoid the worst pitfalls.
Some of the more frustrating problems I've experienced involve going out of my way for something that does not fit what I am looking for. A waste of both time and money. So if I am looking for a great crabcake, don't tell me about a fantastic one... and after I drive there I find it is loaded with shrimp. Great - if that's the way you like your crabcake, by all means recommend it, and I'd like to hear about it. But at least warn me about the shrimp, because that is not at all what I am looking for, and I will probably be disappointed.
Let me know if you think there is something wrong with this approach. Overall, I try to let the OP dictate the terms.