Michael Ray is in the middle of explaining something complex. Every second Wednesday of the month, Ray hosts a meetup group to talk about the state of the bitcoin, its convenience and why it could be the next great thing spawned from the internet.

His mission? Get the knowledge of digital currency out to just about anyone who'll listen. But he had to start small, so hosting the meetup is where he began almost one year ago. His audience congregated in the back room of a coffee shop for a recent gathering. He rattled off answers to questions, big and small.

In walked someone carrying a small, blockish thing with a golden-yellow bitcoin logo on its side.

"Here's the man with the machine," Ray says. The room lightens with a slight air of amusement as the man lugs in a portable bitcoin ATM. He sits the machine, used to convert dollars into the virtual money, down on a table.

The ATM, Ray says, touches on one of the thorniest issues concerning bitcoin: money laundering. Some say the anonymous nature of transactions could make the bitcoin more useful for illegal activity. And federal agencies remain skeptical of it. But Ray and other devotees are still positive on its prospects for entering the mainstream.

Michael Ray of Mobile, Ala., sits next to a portable bitcoin ATM as he takes part in a Mobile bitcoin meet up at Serda's Coffee Company on Wednesday March 11, 2015 in Mobile, Ala. (Sharon Steinmann/ssteinmann@al.com)

Oliver Calaminus, the ATM's owner, said a lawyer told him not to use the machine for a money-making business, warning him that he could run afoul of anti-money laundering laws. "He said they'll take me to jail," Calaminus said.

He had bought the machine off eBay. "This is the cheapest one; this is about a grand," Calaminus said, "but I'll sell it to anybody for about $1,500."

There remain more questions than answers when it comes to trading cash to receive bitcoin. The currency is regulated, but not really regulated. There's no central bank in the bitcoin space. And some say its more akin to a commodity, like coffee or rice.

This has not stopped big-name retailers like Overstock.com and TigerDirect, among others, from accepting bitcoin. Last year, there were more than 320 ATMS operating -- mostly in cafes, restaurants and other retailers -- around the world, according to CoinDesk.

The news and information service said it expects that number to more than double in 2015, even as the value of bitcoin has taken a bruising in the last year. Its market price began to fall after hitting its peak at $951 on Jan. 6, and was coursing through several troughs around this time last year. By the end of 2014, about one-third of its value was gone.

None of this has deterred consumers from signing up for the digital "wallets" that allow you to transact in bitcoin. Nor has it stopped a lot of the intrigue around the digital currency that could all at once reshape the way we spend money. But people have to use it first.

TWO YEARS AGO, bitcoin would have been considered a good business opportunity. Its price was on the upswing, trading for as much as $1,400. Several corporate-types were clamoring around the currency then, trying to get in on the action.

"For a while bitcoin was a great investment -- you wanted some bitcoin because the value was going to go up and up and up," said Gary Warner, who runs the Center for Information Assurance and Joint Forensics Research at the University of Alabama at Birmingham.

Then, Warner said, there was the break-in at Mt. Gox, a bitcoin exchange based in Japan that lost nearly $63.6 million after a hacking attack about one year ago. "Then the value of bitcoin dropped astronomically."

Warner, like many, is skeptical of bitcoin's chances for survival beyond a small cache of early adopters interested in new technology.

"In our kinds of towns, if you're the only business that accepts bitcoin you're going to get a certain following from people that think it's cool," Warner said. "There is an appeal if you're trying to appeal to a technical audience; the tech audience is the adopters here."

Participants take part in a Mobile bitcoin meet up at Serda's Coffee Company on Wednesday March 11, 2015 in Mobile, Ala. (Sharon Steinmann/ssteinmann@al.com)

Today, its popularity is fueled largely by enthusiasts like Ray, but bitcoin has not quite taken off with local retailers around Mobile. Serda's Coffee Co., the host location of the night's meetup, accepted it for about one week. But no one used it except Ray, said John Serda, the coffee shop's owner. He logged one other purchase online.

But the flagging interest among customers was beside the point, Serda said. "It just takes forever to take bitcoin at our register."

Serda once used an iPhone app to accept payments. Because no company in particular owns bitcoin, there's no built in function with his point-of-sale system like a credit or debit card.

About a year ago, Ray said he started helping other retailers in the area get their own "exchanges," too. "At the time I was really excited about any arrangement," he said, "and as I've come to learn more I've found that -- at least for now -- bitcoin is more pertinent to online retail situations."

FOR THE SEVEN or so people who have gathered -- including a retired lawyer, an IT administrator and real estate brokers -- the night is more about education. Technology moves so fast, they say, and the meetup is a way to keep tabs on one of the potential changes.

All the intrigue surrounding bitcoin felt the same to Calaminus, the bitcoin ATM owner, as the buzz about the Internet and email when they first became services for the general public. "I was right about them all," he said. And each are now counted as essential.

"I come to these bitcoin meetings just to learn," said James W. Lyon, a broker with Exit Realty in Mobile. Lyon, could recall when credit cards were considered new. "It must have been the toughest sale to try and get a merchant to get a credit card machine," he said.

Lyon noted that there has already been significant real estate purchased with bitcoin. He doesn't want to fall behind the times. "Bitcoin is virtual money and it's coming, but it's controversial...," he said. "We just have to be aware and learn."

Update: This post was updated to correct the date the bitcoin meetup is held on March 28.