Interview by Alex Kantrowitz, contributor

See those Facebook “Like” buttons all over the web? If Meetup CEO Scott Heiferman has his way, his Meetup Everywhere buttons will be next. The New York-based social networking site, which currently has around 79,000 groups of people with common interests that, well, meet up, recently launched Meetup Everywhere, a widget that can be embedded into any web page, enabling visitors to plan meetups around the topics they’re reading about.

While just released two months ago, Meetup Everywhere is taking off fast. It is already in use by the Huffington Post, Mashable, Foursquare, Tech Crunch and, just last week, YouTube joined up. Yes, it’s possible to meet up to discuss OMG cat.

The Huffington Post, one of the earliest adopters, asked its readers to meet and talk about the Gulf Oil spill early in June. Since that posting, 1,812 people in 25 countries have taken part in 439 Meetups, all centered around brainstorming and taking action to help blunt the spill’s impact.

Meetup CEO Scott Heiferman usually works from behind the scenes, but he recently sat down with Fortune to discuss Meetup Everywhere and how it fits into his company’s ultimate goal: “a meetup everywhere about most everything.”

How far integrated into everyday life do you think Meetup Everywhere can actually become?

Anything in the world can be a stimulus for a meet up. And it should be. It seems like an inevitable part of the future. If there’s something that you’re fired up about that you just read in the paper, whether Nicholas Kristof or Rachel Maddow or Glenn Beck are writing about it, there should be a concentration of twelve people within two blocks of you who really want to have a conversation about it, and are willing to do so tomorrow during lunch hour. That’s where we want to see the world go.

How did you test Meetup Everywhere? Did you use focus groups or other market research?

We built Meetup Everywhere with absolutely nothing written down. There was no product spec, no mock-up, no strategy document. Absolutely nothing was written on paper or on screen about what this thing is, or what it’s going to be, or how we’re going to do it, or why we’re going to do it, or how we should do it. It just sort of naturally evolved out of conversations here, and our VP of engineering, Gary Burns, just started hacking it up one day, and we said, “let’s do this.” No focus groups or anything. It does seem funny to me that we have something that we think could really be transformative in so many ways and there’s not a paragraph written about it internally.

You realize you’re trying to spur some serious behavioral change with Meetup Everywhere. How do you expect to overcome the challenges that come along with trying to get people to change the way they live their lives?

I’ve got tens of thousands of years of human evolution and behavior behind me to say that people like the idea of real life, face-to-face conversation about something that’s important to them. I’m not trying to bring in this whole new behavior. I’m trying to bring in a behavior that throughout human history has come pretty natural. That said, it’s definitely a shift.

The behavior of saying your customers may want to meet up with each other and talk about your product or service, in a culture where we’re just hermetically sealed in our homes and we’re scared of strangers, that sounds crazy. But that’s going to be the future.

Meetup has no public relations team and you’ve been known to generally avoid media attention. Why are you sitting here now?

The idea is have it [Meetup] be a great product. And as people use it, they will come to see it and understand it, and eventually they will want to use it at their own organizations or their own companies. We’ve been really lucky in having great initial launch partners and, as you see other ones come through, it’s coming from people at those organizations having experienced it and bringing it back it to their own organization.

That said, we are still not having a PR department, but for the first time ever, I’ve had to change my opinion and change course.

What we’ve realized is that, in the case of Meetup Everywhere, where its organizations, businesses, non profits using it, they really do have a lot of questions and it is so non-intuitive. I’m here because we want people to understand Meetup Everywhere.

Do you think that Meetup has reached a growth ceiling?

We haven’t even hit our tipping point yet. We have not scratched the surface of what’s possible, in fact, Meetup Everywhere gave us this awesome wake-up call. If the Huffington Post can put a little link somewhere and see all these meetups pop up, if authors can post on their blog that their readers should meet up with each other, if a business can do this simple nudge for people to meet up, and people want to meet up, what it tells us is that there’s a lot more potential for Meetup in general than we’ve seen so far.

Ten years down the road, what will Meetup look like?

Could there be a company that has a footprint of serving a billion people with only 200 people on staff? That would be ideal.