Funny, your phrase "what are those little people statues at the 14th St. 8th Ave. subway station" returns http://en.wikipedia.org/wiki/Life_Underground as the first response for me, which I assume is what you are looking for. It seems that many of the examples are just location based information that is better served via map.
I never bothered to search that exact phrasing of the question. When I initially went looking I used a few phrases that didn't turn up anything. It seems like "statues" or "sculptures" are the operative words. Try "decorations" (which is what I tried), and you won't get the same result. Getting the phrasing just right is an unnecessary hurdle. Had I posted a picture to Jelly, it would've spoken for itself.
So considering my failings, I actually see this exchange in favor of Jelly or a service like it. After all, it was you, someone part of my social network, who gave me the answer I was looking for, not google.
Take for example this search for the statue of Anteros, in Piccadilly Circus: https://www.google.co.uk/search?q=statue+in+london+with+bow
Conversely, I bet posting a photo to Jelly would get me an answer. And it only becomes more likely that my friends (and their friends) will find an answer easier than I can the more obscure and difficult to search for the subject is.
Search engines are getting much better at interpreting the question you wanted to ask from the question you actually asked - "Did you mean..." - but they still have a way to go before they can do a better job than a human.
I don't see why not. Quite a few of my friends are leaving social networks these days, mostly due to the lack of a specific purpose. I.e too much non sense. So I can totally see hooking up to new social networks that have specific purposes that accommodate my needs. I don't have an immediate need for this one right now, but I'm not adverse to trying it should I come across a situation where I do.
Wait... I thought jelly works on top of existing social networks, no?