I feel like there is definitely something in this basic idea. Although I'm not sure that a rigid 1 mile boundary really makes a whole lot of sense. I'll explain:

I feel like the experience you get with an app like, say, tinder, which lets a user chat to attractive people locally, is really quite an incredible proposition. In tinder's case the hook is that you are chatting to, and then hopefully meeting with, a slice of the local population that you find attractive and that also find you attractive. You both find each other attractive - so you have that in common.

What I find myself hankering after more and more though is a service that lets you discover a slice of the local population with which you have other things in common. Not a dating app, but rather an app where I could chat about a topic I'm interested in (technology, hockey, model trains, tiddlywinks, you name it) with people who are also interested in that topic and then hopefully connect and meet up with those people who all happen to live fairly locally.

Hacker News for instance is great for tech chat, but as someone who lives a long long way from SV I find that it's much tougher to actually MEET people who share my interest in tech. There are tech events going on around where I live, but it's still an intimidating prospect showing up to some niche interest event when you haven't met or chatted to anyone there before. Technology is big interest of mine, so in the end I did seek out events and other ways to connect to like-minded people. But I have a much less active interest in, say, sailing. It wouldn't normally occur to me to go seek out a sailing club or a sailing meetup of some kind locally, but I might still like to chat about it. And chatting about it with similarly interested people nearby might lead me eventually to go along to such an event and meet new friends and try new experiences.

I feel like Kiwichat goes some way towards implementing that vision, but I just signed in, and my one mile radius shows no chats nearby. I live in Edinburgh, in Scotland, which isn't always the first city to bustle with new technology, but it's maybe 5 or 10 miles in diameter, and I have no way of knowing if someone else in Edinburgh is using this site, but from a location only a couple of miles away. Maybe I'm missing out on some new connection, or experience, all because I couldn't put my radius up to a level that makes sense for me personally.

I feel like this is close to the app I really want. Closer than anything I've seen so far, but still sadly quite a way off. It says on your landing page that it's for "events, meetups, or just chatting with people nearby e.g. students in your campus". If you're at an event or meetup then you are already most of the way there and you are probably talking in person. If you're on a small campus then this might serve the need I'm looking for. But if your campus is big and spread out (like mine was at university), or you live in a small city or town and want to chat to people that you could easily meet, then it's just not serving that need... Yet.

In terms of execution though it looks great, the sign in experience is pretty much flawless. Congrats on your launch.