We go to conferences to meet people, whether for business or personal reasons, and yet often I meet far fewer than I hope to. Inside a crowded convention space, things can turn cliquish in a hurry. Come lunch time, I’m right back to being the new kid at school, sheepishly hunting for a table that will accept me. Want to know anything about the strangers around you? Just read the fine print on their name badge, and do it before they notice and think you’re staring at their chest.

Little about this experience has changed in the last 50 years, and technological efforts to reinvent it have largely stalled out. Glassboard, a private messaging app often recommended for conference-goers, shut down last November. Lanyrd, a full-featured app for discovering and better enjoying conferences, was acquired by Eventbrite in 2013 and hasn’t updated its apps in more than a year. But at the XOXO Festival in Portland this weekend, I saw a new app remaking the conference experience in more ways than I could count. And the app, strangely enough, is Slack.

Slack, of course, is the team collaboration app that rocketed to 1 million daily users and a $2.8 billion valuation in barely a year and a half. At its simplest, it’s a chat room that lives on your laptop and mobile devices. But once Slack is connected to all the other apps and services used by your team, it becomes the central communication hub for your entire organization. When Slack first came out the thought was that it could "kill email." But as great a feat as that might be, Slack’s ultimate impact may actually be larger. It may look like a chatroom, but when you see all the ways people are now using it, Slack starts to feel like anything but.

A new social app advancing into the mainstream

Just as South By Southwest became famous toward the end of the last decade for the way it propelled social apps into the mainstream, there was talk this weekend that XOXO might serve the same function for Slack. As Rex Sorgatz, a longtime blogger and conference attendee, put it:

Slack : XOXO 2015 :: Twitter : SXSW 2007 — Rex Sorgatz (@fimoculous) September 12, 2015

Here’s how it played out at XOXO Festival, the 4-year-old creative playground curated by internet heroes Andy Baio and Andy McMillan. The Andys, as they are collectively known, bring together comic-book artists, web developers, musicians, designers, startup CEOs, and other creative types to discuss the challenges and triumphs of making things independently, online and off. They limit attendance to about 1,000 people chosen through a lottery; the people who attend include many of the forward-thinking types you once found at South By Southwest. And this year, more than a month before the festival, they created a Slack team that anyone attending was free to join. (Slack was among the festival’s sponsors.)

By the time XOXO got underway, attendees had created more than 150 channels to discuss and organize around nearly every topic imaginable. The most widely read channels were "the commons," where the Andys posted news about the festival relevant to all attendees. But subgroups formed in a hurry. There were channels for discussing accessibility; channels for singles and the polyamorous; channels for people interested in cannabis; channels for attendees who identify as LGBT. Some channels had dozens of members; others had 10 or fewer.

A thriving hub of conversation

The result was that by the time many attendees arrived in Portland, there was already a subset of their fellow festival-goers waiting to greet them. And throughout the three days of XOXO, Slack was a thriving hub of conversation, offering a place for attendees to encourage and congratulate speakers, ask questions about the event’s code of conduct, and find like-minded souls with whom to sneak out and grab a beer, or a bite, or whatever.

Toward the end of the conference, I posted in the commons asking attendees how Slack had changed the festival experience for them. I received a slew of replies (via Slack!), which I’m sharing with their permission. (Baio asked me not to quote anything from public Slack channels, given the intimate nature of much of the discussion.) "It was fantastic to quickly align with people on interests," attendee David Chien told me. "It meant the difference between a cold introduction during the densely packed conference days to a nice relaxing meeting of Internet friends." Chien’s wife met new friends on Slack before the conference using a channel called #penpals; Chien joined the #beer channel and brought some regional brews to a beer-lover’s meetup organized by attendees.

Conference-goers who want to connect have many options, but the people I spoke with said they found Slack more fun to use. "It’s just much easier to use and less noisy than Facebook, Twitter or custom apps," attendee Clay Smith told me. "The really useful thing was being able to join channels that I was interested in (say #cocktails) and be connected with people who shared the same interests." But uses got much more creative — during a delayed flight from San Francisco to Portland, some XOXO attendees set up a channel for the delayed flight and entertained one another while they waited for it to take off.

The result was a conference that was notably friendlier to introverts than normal. "Normally, coming to a conference without a buddy means that I’d have to basically cold-meet people, which is really challenging for me," attendee Pablo Defendini told me. "More often than not, I’ll end up in a corner, and then I’ll just go home early. But having met people in the XOXO Slack ahead of time made going up to people much less intimidating."

"Slack made going up to people much less intimidating."

Slack also proved useful to the folks running the conference. The Andys said onstage that they had found it indispensable for a range of tasks, and a festival volunteer told me Slack was their primary channel for coordinating their efforts. "It’s great because we all should have access to the same information so we are on the same page," said Ben Elder, the volunteer. "It really minimizes the telephone effect of information getting garbled or not shared." It also enabled volunteers to make certain standard functions virtual: the volunteers built a lost and found in Slack, and used it as the primary resource for festival-goers who had lost an item.

Slack’s integrations with other apps and services led to further creative uses. Aaron Parecki, a developer and conference attendee, created a #shuttle channel to post the location of the XOXO shuttle as it traveled between the festival hotels and the conference grounds. And when Gamergaters began assaulting the festival’s hashtag, #xoxofest, in hopes of rendering it unusable, Parecki built a Slack room that showed only attendees’ tweets from the festival. Just to underline that — Parecki rebuilt Twitter inside of Slack using only tweets from attendees. And it worked flawlessly.

Perhaps for that reason, Slack as a conference tool seems likely to spread. "I’m already scheming to bring it to Chef’s Week Portland next year," Drew Tyson, a Chef’s Week organizer and XOXO attendee, told me via Slack.

Meanwhile, XOXO’s Slack channel isn’t going anywhere — the Andys announced at the festival’s closing that they plan to keep it open indefinitely. In part, this serves their ambition to turn XOXO into a year-round phenomenon; they’re preparing to open a permanent co-working and event space later this year.

"I'm already scheming to bring it to Chef's Week Portland next year."

But it also enables the community that developed over the past several months to keep interacting, regardless of whether they ever attend another festival in person. (The Andys have not yet committed to a fifth XOXO; each year they warn the crowd that the current festival could be their last.) "I’ve made lots of great connections here," Defendini told me. "And it’s been really helpful to know that, regardless of whether I caught a person’s email or Twitter handle, I can look them up in the Slack directory and ping them."

Slack won’t work for every conference. With thousands of attendees, public channels could get very noisy. (Depending on which service plan organizers pick, inviting thousands of attendees to Slack could get expensive, too.) But I wouldn’t be surprised if, over the next year, we saw more small- and medium-sized conferences and festivals adopting Slack as a place to bridge the online and offline worlds. It’s already starting to happen, and Slack hasn’t really even started to try.