Steven Isaacs — @mr_isaacs on Twitter — is a full-time technology teacher in Baskingridge, N.J. He's also the co-founder of a new festival that set the Guinness World Record for largest gathering dedicated to a single video game.

The game that cements both halves of his life together? Minecraft.

(In case you haven't heard, Minecraft, originally developed by Markus Persson of Sweden, offers players the chance to build a 3-D world out of "blocks." Since its release in 2009, Minecraft has sold more than 121 million copies, making it the best-selling game of all time after another blocky favorite, Tetris.)

Other games allow you to fight monsters, construct giant castles, build power plants, navigate mazes, chop down trees for wood, survive in the wilderness or band together into guilds. Minecraft has all of the above. It is so open-ended, in fact, that some refer to it as a platform instead of a game, or an "infinite Lego set."

It wasn't long before an advance guard of teachers like Isaac started using the game in classrooms. One, Joel Levin of New York, co-founded a company called TeacherGaming which came out with a modified classroom version, MinecraftEdu.

In 2014, Microsoft bought Minecraft. This past school year, the company purchased MinecraftEdu and launched an official Minecraft: Education Edition.

Teachers are using Minecraft in every imaginable subject, from literature to social studies to math. Build a 3-D diorama of an archaeological dig; retell a Japanese folktale; test bridge designs in different materials. Isaacs' students build video games within the game.

In Diane Main's computer science class at a private school in San Jose, students interview each other and then build each other's dream homes, based on what they learn about their "clients."

"It's the weirdest thing in the world to think about," muses Meenoo Rami. A 10-year classroom veteran and national board certified teacher, Rami now works for Microsoft, spreading the Minecraft gospel to fellow teachers.

"A little tiny company creates a game and it goes insane," she says. "It's not meant for learning, but some adventurous teachers think it might be good for learning" and start doing, she says, "super cool stuff."

Then, a giant corporation gets ahold of it.

The acquisition by Microsoft, and the transition from Edu to EE, has set up a classic tension: What happens when a phenomenon nurtured by amateurs suddenly goes mainstream? And will it be good or bad for students?

At the skate park

In the Edu days, teachers set up and maintained their own servers — a server is a single version of the game that a certain number of users can play in together. This required some technical know-how, but also allowed for lots of experimentation and customization, or "mods".

"Scrappy educators and hackers and YouTubers kept adding stuff on, and it was very much an organic, geek-led movement," says Mimi Ito, a cultural anthropologist at UC Irvine who studies how children and teens use media. She is also the founder of an online Minecraft summer camp.

Ito compares the game to a skateboarding park: a place that kids flock to and have a blast while also picking up wicked cool new tricks. "Kids are mostly hanging out, but they're also learning from each other," she explains. "Some are more advanced and are displaying their skills, so there are open invites to level up."

Minecraft as a teaching tool wraps up so many contemporary trends in education. It's inherently collaborative. "The multiplayer part is really at the heart of it," says Isaacs, noting that many other tech tools available are, at best, "two kids, one computer."

It's creative, because it's almost entirely open-ended.

And new features keep expanding the possibilities. The Minecraft material "redstone," which simulates electrical circuits, offers the chance to layer-in engineering lessons too. Code Builder allows students to use programming tools to perform tasks within the game.

Stampy Cat and Gizzy Gazza, and Office365

But the most important factor that makes teachers gravitate toward Minecraft is that so many, many kids really love it.

That's what Isaacs discovered when more than 12,000 "crazed fans and their parents" paid between $49 and $79 to attend the first Minefaire, last October in Philadelphia. They're fans not only of the game itself, but of YouTube celebrities with millions of subscribers. Essentially, Minecraft has its own rock stars, with names like Mr Stampy Cat and Gizzy Gazza.

With all this grassroots enthusiasm, it's not surprising that Microsoft would identify Minecraft as an important trend. The tech giant has been eager to re-establish itself in the classroom market. Microsoft Office was once standard in schools. But with Apple and Google now dominating in devices and Google in free classroom software, the company needed a new inroad.

Microsoft's Minecraft is a little different than what came before. The Education Edition conforms better to traditional lesson planning, particularly grading. For example, you can take pictures of what you built with a "Camera" and create a "Portfolio" with commentary to document your project.

If you don't want students shooting off fire cannons in the middle of a science lesson, you can block that feature. There is a "Classroom" mode and even "chalkboards."

The Education Edition also has different licensing that makes it, in most cases, more expensive for school districts. It requires schools to be registered on Microsoft's platform.

Taken together, the changes have some observers wondering whether the company is going to turn Minecraft into a product, with all the ubiquity — and all the fun — of PowerPoint or Office.

'The scrappy, user-generated Minecraft'

"There's some danger in having it become more packaged and commercial, losing that energy that was more about this scrappy user-generated Minecraft," says Ito. In the old days, she explained, teachers bought MinecraftEdu once, with licenses for each machine. Students kept their individual accounts from year to year, and inside and outside school, as they wished.

Now, Microsoft requires that teachers buy licenses for each student who uses Minecraft — $5 per user per year — and to renew them every year. It takes less technical know-how than maintaining a server, but in most cases this is far more expensive than the MinecraftEdu model.

"It's an equity issue," says Diane Main, the teacher in San Jose.

Microsoft's Rami responds that Minecraft is a great value compared with other ed-tech products. There are bulk discounts, and the company is exploring need-based discounting as well.

On Minecraft Education's official message boards, there are complaints about the new sales model: "As an educator I look at this and I see opportunity," one teacher wrote. "Microsoft looked at it and said: 'How can I make a better profit.' "

Rami says the company is trying its best to listen to all the feedback. Microsoft has recruited 60 of the most enthusiastic Minecraft teachers, in 20 countries, to serve as "mentors." They "inform our work by giving us feedback and keep us honest and grounded to the work that teachers actually do in the classroom." Main and Isaacs are both mentors.

Mentors help bring other teachers on board with Education Edition and provide suggestions for new features.

"It's a two-way pipeline of feedback," Main says. This is a voluntary position, but there's also the potential to earn money by leading professional-development sessions.

In the process of cultivating this community, Microsoft has converted potential critics into supporters.

"Microsoft has been fighting an image problem, but this has softened me toward Microsoft in general," Main says.

"They're one of the model companies in terms of ed-tech," agrees Isaacs.

But an issue with the pricing and licensing changes remains, says Ito. Rather than accounts belonging to individual students, they belong to the school, like a textbook that is yours for just one year.

"It's pretty significant," says Ito. "The identity lives within the Microsoft suite. It's not a user identity that the kid retains and has at home." For that reason, says Ito, many of the old-school Minecraft teachers are holding on to their MinecraftEdu licenses for now.

Main is one of them. Despite her status as a mentor, she says she can't use Minecraft: Education Edition in her own classes, because her projects depend on students being able to sign on from home and collaborate. She says she has hope that the company will soon figure out a workaround, based on the progress they've made on other issues raised by teachers in the last 18 months.

Nevertheless, the shift away from individual accounts to school-based logins is part of a bigger transition that may be inevitable.

The reason teachers brought Minecraft into the classroom is because young people love it. But anything that is incorporated into schools is touched by standards, tests and grades, and often becomes mandatory.

Isaacs and Main are using Minecraft as a fun gateway to other kinds of learning with tech — and an appeal to students who don't necessarily see themselves as stereotypical coders.

But by definition, if Minecraft becomes standard issue in more schools, it will no longer be a passionate, personal discovery for most students, or teachers for that matter.

Will it still have the same appeal and foster the same engagement?

Main says she's had this exact debate with one of her students, a former homeschooler. "She was talking about the risk of making Minecraft suck by schoolifying it. And I said, 'Just because you schoolify it doesn't mean you suckify it.' It doesn't matter what it is, anything can be done badly or done well."

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