So you think you'll have your metaverse under control? Think again! (CW: nudity mentioned, sex mentioned, BDSM mentioned)

Okay, so you're working on creating a metaverse. Maybe proprietary, non-free and closed-source, maybe free-as-in-freedom and open-source. Maybe a walled garden, maybe something actually decentralised with worlds that are federated with one another, maybe even "the Metaverse" that shall become an Internet-wide standard or a least a part of it.

Of course, you're a professional. You think you've got everything down pat. No, you've never been in a virtual world. Or maybe you've worn a VR headset for a couple minutes once or twice before you've started your development. But you think you're as much of a virtual worlds expert as they ever come, simply because you've grokked the technology, and technology is all there is to virtual worlds.

And you think that you, as the creator of this platform, have everything fully under control.

My prediction as a several-years-long user of virtual worlds: You'll fall flat on your face. You'll be caught off-guard by and overrun with unexpected user-driven developments in your virtual worlds that neither you nor your worlds are prepared for. And you will have to doubt the two above paragraphs.

And here's why:

• Virtual worlds that absolutely require a VR headset won't become popular. Virtual worlds that absolutely require a VR headset from one specific brand will become even less popular. All the popular worlds out there can be used as "pancakes" on a run-of-the-mill desktop or laptop computer with a run-of-the-mill 2-D screen that folks have at hand anyway.
• The more limited your avatars are (e.g. no lower body/legs or no limbs, just hands and feet), the higher the probability that everyone will laugh about them. And compare them to Second Life.
• At this point, you'll find out that Second Life itself is not only unexpectedly still alive after two decades, but it has evolved a lot since 2008. At least on the desktop, that's your competition. Soon on phones as well. And it doesn't need simplified, cartoonish avatars in simplified, cartoonish worlds because it isn't made to always deliver 60fps on fanless mobile hardware, so it can go all the way with graphical details.
• If you leave world-building to corporate world owners and their paid designers, you have to pay your designers well for years and decades to come so they keep on building. Otherwise, your world will go stale because everyone will have seen everything, and nobody will want to come visit it anymore except for newbies. The key to successful virtual worlds is giving users the opportunity to build. And "users" doesn't only mean rich celebrities who pay virtual land admins to plop down their designer-built mansions on their ten-million-dollar parcels.
• And even building won't happen if you make it too difficult for users to build. Guess why Second Life and OpenSim are so popular.
• Virtual headquarters of cool brands only stay cool and exciting and interesting for so long and for so many people. Especially if they can't enter them. Ditto virtual mantions owned by celebrities.
• If there's the possibility to attach anything to an avatar, people will make avatar design more flexible than what the designers have planned.
• If you have professionals as your target audience, and your avatars have lower bodies, female users will demand appropriate business attire. This means you'll have to make skirts possible.
• Your standardised skirts which have worked pretty well under your lab conditions will show rampant leg clipping in daily use. You'll learn that Sinespace, Vircadia and Overte exist by finding out that they've got their own physics-based solution for skirts. And for long hair.
• Speaking of business attire, high heels. If avatars have feet, high heels will be requested. And not necessarily with only one height. Both the virtual world standard you're building on and your engine will only support flat feet from the beginning because who could really expect this?! So implementing high heels requires either re-writing half the avatar standard and half the avatar engine, also to account for the avatar being "taller" on heels, or an ugly kluge that nobody really is happy with.
• Alts. People will have alts.
  If you ask someone interested in virtual worlds who has never been in a virtual world or maybe just for business purposes, they'll tell you that everyone will have a "digital twin" avatar in The Metaverse in the future. As in exactly one avatar.
  Ask actual spare-time users of virtual worlds, and many will laugh and tell you they've got several avatars already now. In one and the same world.
  In a decentralised metaverse, this will be even more likely and impossible to prevent. Just look at OpenSim where almost everyone who has been around for at least a couple of months has avatars in multiple worlds, multiple grids, even though you can teleport between grids, between servers with different owners and operators running different versions of OpenSim, using the same avatar. And having multiple avatars with different identities isn't rare either, even within the same grid.
• Crossplayers. If the avatar looks female, that doesn't necessarily mean that there's a female user behind it. Especially not if text chat is used instead of voice.
• If kids can use your metaverse, and there's any incentive for kids to use your metaverse, kids will use your metaverse. Especially if it can work as a "pancake" without requiring a headset. And they're very likely to get themselves cool "grown-up" avatars, regardless of whether or not underage-looking avatars are possible/available or not. They're kids after all. Why should they only play themselves in-world if they can also play someone else just like they often do in real life?
• Vice versa, just because an avatar looks like a kid, doesn't mean the user behind the avatar is one.
• Nudity. And naughty stuff all the way to virtual sex. It will happen. Users will find a way. Maybe not right away, but they will.
  You may design your world for people to build virtual office spaces, virtual after-work dance clubs and virtual live music venues. But they will build fully-functional virtual swinger clubs and virtual BDSM dungeons once they figure out how.
  And you'll be so unprepared that banning everything remotely naughty out-right, while being a game of Whack-a-Mole itself and not even backed by actual rules at first, will be vastly easier than implementing content ratings, especially regional content ratings.
• A free, open-source, decentralised metaverse will not only consist of worlds operated by staffs of hired full-time professionals. There will be private people running their own worlds, either on a machine at home or on rented Web space.
• This also means that you can't bet on land scarcity and ask premium prices for your land in a free, decentralised metaverse. Why should people spend ridiculous amounts of money on chunks of your land if they can make their own land anytime?
• The easier it becomes for private individuals to set up their own worlds in a decentralised metaverse, the more people who really shouldn't operate any kind of server will do so nonetheless. And the more people will do so just to circumvent bans because nobody can ban them from their own worlds. Another two lessons OpenSim has learned, but nobody will learn from OpenSim as long as nobody knows that OpenSim exists, and as long as everyone only acknowledges virtual worlds that have a CEO.
• Different worlds, different rules. You'll find out quickly enough how this applies to decentralised networks of virtual worlds. The OpenSim community already did: Second Life's General/Mature/Adult content rating definitions are pretty much useless if each grid can re-define them as it pleases. General-rated clothing-optional beaches are just as real as places that are both Adult-rated and G-rated and only use the Adult rating to keep avatars looking like children out.
• Different worlds, different server software versions. In a decentralised metaverse based on anything designed or developed centrally, be it the server software, be it the standards definition, it's impossible to guarantee that all worlds always run the exact same version. You'll find out the hard way when a compatibility-breaking upgrade creates a rift through your precious metaverse between the worlds that have upgraded and those that haven't.
  Don't count on all worlds upgrading ASAP either. There will be worlds several years worth of new releases behind for whichever reasons, and be it because world owners disappear under a rock for years while keeping their worlds online.
• A decentralised and truly open-source metaverse will inevitably mean forks. And the forks want to stay compatible with the original. This also means that if you mess up, and you refuse to admit and fix your mistake, world owners may increasingly switch to forks and abandon your original project altogether.
• If you implement the possibility for one world to completely block another world, in-bound, out-bound or both, this feature will be used in feuds and other kerfuffles between worlds. Or between their admins. Or between the admin of one world and one user of another.
  If you don't implement it, users of rogue worlds can run rampant, and stopping them will be difficult or out-right impossible.
• Any innovation, any new feature you add to your virtual world system will not necessarily only be used the way you intended and designed it for. Never underestimate the creativity of your users.

Those who really know their way around virtual worlds can tell you all this and more.

But they aren't other creators of new virtual worlds. They aren't virtual world CEOs. I guess they aren't even Philip Rosedale, and on top of inventing, creating and leading Second Life, this guy has also actually read Snow Crash.

They aren't academic researchers either who interview virtual world designers and virtual world CEOs and other virtual world researchers and occasionally read what mass media or tech media write about virtual worlds without ever spending more than 15 minutes in a virtual world themselves.

No, they're the people who actually use virtual worlds. Regularly. A lot. And I don't mean the newfangled proof-of-concept stuff or small worlds specialised for exactly one purpose, one task.

The actual virtual world experts are the veterans of big, established, popular worlds like Second Life, including those Lindens who actually go in-world and thus have stories to tell. And the real experts on free, open-source, decentralised virtual worlds are the OpenSim veterans.

They haven't just heard or read about something being done in virtual worlds. They've witnessed it being done first-hand. Or they've actually done it themselves.