The conference occupied only two 400-seat presentation halls and two short stretches of vendors, all tucked neatly into a second-floor corner of the immense Miami Beach Convention Center. The mood and mode were enthusiastic, casual, and open. The openness extended to the free-flowing mix of hacktivists, venture capitalists, and 19-year-old savant programmers. By the middle of Saturday, the event space was full to overflowing — attendance had been projected at 500, but quickly swelled to more than 1,200, and the packed halls were charged with an air of frenetic joy. This was, by all accounts, the largest bitcoin conference ever — until, it’s almost certain, the next one.

The NABC was organized by Moe Levin, a Canadian who looks as improbably young as most of the engineers, programmers, and entrepreneurs at the heart of the event. NABC is the second conference Levin has organized, after putting together the European Bitcoin Conference in September of 2013, and he’s as stunned by the explosive growth in interest as anyone. “[At conferences] a year ago, it was 50 people.” The conference also displayed the wild unevenness of current development in the space. Lithe booth babes prowled the slick display of payment processor BitPay, while scrappier groups were identified only by photocopied sheets of A4 taped to the front edge of a folding table. The business cards being cheerfully passed around ranged from cracker-box flimsy to rigid slates with bezeled edges sharp enough to fell an enemy ninja.

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To investor Michael Terpin, co-founder of the investment consortium BitAngels, it all looked and felt like the first Internet World conference, which he attended in 1994. “In ’94, you had a tabletop, with [executives] from Lycos handing out t-shirts.” No one then really knew that this whole Internet thing would go anywhere, or that Lycos would go on to become, for a time, the most visited destination on it. At NABC, it was the young founders, CEOs, and head technologists of bitcoin-related companies who stood behind folding tables doing retail P.R. with candy bars, lanyards, and playing cards.

Represented teams included key infrastructural players like payment processor BitPay, the transfer service ZipZap, and mining hardware manufacturer KNCMiner — as well as earnest hangers-on like a yoga teacher offering DVDs for bitcoin. Sprouting buds of the possible bitcoin future could be seen everywhere. What looked like a young teenager along with a Lana Del Rey lookalike stood nervously behind the table for Kraken, a bitcoin foreign exchange platform they had helped build. Three pale, smiling young men set up LCD screens showing their gaming service, Leetcoin, which lets players compete for tiny amounts of bitcoin in online matches of adrenalin-fueled first-person shooter video games. Leetcoin is a thrilling but ominous prospect for gaming fans and addiction counselors, and wouldn’t be possible without bitcoin’s ability to send small sums for cheap or free.

In the lecture halls, anti-government Libertarians handed the mic off to experienced corporate lawyers who discussed likely regulatory scenarios. The rock star of the conference was Vitalik Buterin, a bird-like college dropout who had to be shown how to speak into the microphone before he could explain his invention, the Ethereum protocol. Ethereum is an ambitious effort to build a distributed network similar to bitcoin’s, but hosting a much more robust programming language, enabling it to execute not just currency exchanges, swaps, and stock offerings, but also nonfinancial features like peer-to-peer cloud storage, domain name registration, and something called a Distributed Autonomous Corporation. Buterin received a standing ovation, and as he left the hall was immediately mobbed by a throng of 40 reporters and onlookers hanging on his every word. For the rest of the conference, he wore the dazed, beatific look of Peter Parker after discovering he was Spider-Man.

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Some perspective came from Rik Willard, the suave and imposing representative of MintCombine, a startup incubator dedicated to cryptocurrency projects from New York to Nairobi. Willard said that the more iconoclastic tendencies of the Internet’s pioneers were being smoothed out in the bitcoin world thanks to the presence of tech-boom veterans like himself, who had been through it all before. “In the early Internet, everyone thought that the Internet would change everything, there would be no illiteracy, it would be Xanadu … and it turns out, it’s just really business. And this is a very similar situation.”

Many attendees had specific experience in the payment and transfer businesses that bitcoin promises to upend. In passing, I overheard one gray-haired man in a suit declare that “we tried to do this transaction shit in, like, the mid-‘90s,” shaking his head in seeming disbelief that he was seeing it finally happen. In attendance was payment systems entrepreneur Anil D. Aggarwal, whose TxVia processing platform was sold to Google (GOOG) in 2012 (and who is not to be confused with Anil Aggarwal, one of India’s richest men). Aggarwal stated flatly that “if you’re an individual within the mainstream payments and services industry, and you’re responsible for measuring the impact of potentially disruptive innovations on your organization, you’re paying attention to bitcoin.”

Like Terpin, many who had experienced the first Internet boom were now returning to bitcoin with more capital to work with. BitAngels distributed more than $7 million to bitcoin-related startups in 2013, out of a total of about $100 million entering the space that year, but major cryptocurrency investors like Brock Pierce confidently predict that number will skyrocket in 2014, perhaps even including the first bitcoin-related IPO. Terpin again reminisced about the early days of the Internet: “I remember everyone being shocked when it was announced that Netscape raised $20 million, and [investors] were being criticized for throwing money away. And a year later it was a $2.2 billion dollar IPO.” For the moment, though, that all felt far away — enthusiasm, curiosity, and excitement utterly overwhelmed any sense of VCs and entrepreneurs aggressively pursuing one another. David A. Johnston, another BitAngel and board member of the Mastercoin Foundation, characterized the entire community in terms of collaboration and openness.

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Still, avarice wasn’t totally suppressed. A handful of boiler-room types were scattered around the show floor, sweating through cheap suits as they touted “ridiculously profitable” cloud-based mining services or automated bitcoin trading robots. Enthusiasm shaded into hyperbole, claims of guaranteed returns were thrown around with indictable abandon, and buttonholed interlocutors were encouraged to “reserve your spot now.” One new platform would let users “earn 5% on anything” because “we’re cutting out the middleman” — when in fact, what was being promoted was a kind of digital bucket shop, a casino disguised as a stock exchange. But a critical mass of geeks and quants was on hand to interrogate and expose grifters, some of whom could be spotted carrying off their standees at the end of the first day with the dejected, resentful air of Willie Loman.

Maybe the opportunists will have better luck once events like NABC start to attract a truly mass audience, less packed with canny insiders.  And that day is coming very, very soon. Aggarwal says, “You’re literally measuring a change in the attitude toward bitcoin on a weekly and monthly basis,” which probably means that the sense of Edenic excitement and possibility at NABC has a strict time limit.

“We used to say information wants to be free? I think technology wants to be co-opted,” says Willard. “And those in power tend to co-opt technology at the point where it makes sense.” Darker clouds are already descending on the bitcoin scene, in fact, with Monday’s arrest of Bitcoin Foundation board member Charlie Shrem for money laundering, an event whose fallout still remains unclear. Add to that major regulatory hearings in New York this Tuesday and Wednesday, and the 2014 North American Bitcoin Conference may ultimately be remembered as the last days of bitcoin’s freewheeling, carefree adolescence.

Follow David Z. Morris on Twitter: @davidzmorris.