VMM – Understanding How It Works

VMM - How It WorksViewer-Managed Marketplace is making quite a hit with both Sellers and Buyers at the Second Life Marketplace. The “hit” it’s making is more the absence of complaints than the usual flood of them, but in the process of turning around sometimes it’s necessary to do things kinda backward. What really matters though is that VMM is working. And now it’s up to us to learn how it works and how best to use it.

How It Was – Magic Boxes

Magic Box before VMMThe venerable Magic Box was the original method used to make product deliveries. It was an excellent idea and worked fairly well but suffered some pretty basic technical issues. When properly used, the Magic Box would take commands from the old marketplace then send the requested product to the Customer.

Basically the Magic Box was a storage locker. You had to assemble your product into a single combined Object called a “Product Delivery Box”. You then put the finished Object into one of your Magic Boxes. When a Customer made a purchase, the Marketplace would send a command “Hey! Deliver Product XYZ to Customer ABC Resident.” As long as the Marketplace communications worked, as long as the Magic Box was alive, as long as the Product Delivery Box was in the Magic Box, as long as the Magic Box was able to deliver the Object … (whew!) … the Customer got what they bought.

Okay, not simple. But it worked most of the time!

How It Was – Direct Delivery

VMM predecessor Merchant OutboxSeveral years ago the Marketplace Development Team came up with a streamlined process they called “Direct Delivery“. They were attempting to eliminate the weak link: Magic Boxes. Thus was created the Merchant Outbox. It was just a database server that acted as a Product Storage Locker. Instead of needing to assemble your Product into a single combined Object, you assembled it into Folders and Items then uploaded the entire folder tree into the Merchant Outbox. In essence the Merchant Outbox was a new kind of Magic Box, but it only existed in a Linden Lab server and could only be accessed through the Marketplace web site and special tools in the Viewer.

There was the usual avalanche of issues starting with the initial release of Direct Delivery. However after it stabilized and people got used to it, the number of delivery failures went way down and it took less time to deliver a purchase. There was just one remaining problem with “No Copy” items being sold through the Marketplace: You couldn’t use Direct Delivery. *facepalm* Okay, so Magic Boxes were still needed.

Selling “No Copy” Items

Some very popular products sold within Second Life are made so that only one copy can exist at a time. This method is very much like the Real World. When you go to the store and buy a shirt, you get exactly one shirt. You cannot just magically make more copies of that shirt. You bought one, you got one. Second Life supports this type of product. They are called “No Copy” or “Limited Quantity” items.

But the Marketplace Development Team ran into problems when trying to stash Products in their new Direct Delivery storage locker. It’s a bit technically complicated and not really understood by everyone, but basically the Merchant Outbox was “Owned” by a special Marketplace Avatar. It made it very complicated to handle the ownership changes and Permission changes needed. They finally punted and continued supporting Magic Boxes.

VMM - Burning the Merchant Outbox

The VMM Concept

Clearly they couldn’t leave the older Magic Boxes in service much longer. In order to solve the problems created by Direct Delivery, they needed a new method of delivering Products. But the new method had to solve the remaining problems and absolutely had to be capable of selling No Copy items. Since the problem was the special Marketplace Avatar in the middle, why not just get rid of the Middleman? Just transfer the Product directly from the Seller’s Inventory right into the Buyer’s Inventory? Simple!

Note: Magic Boxes do it that way too. Ownership of the Product Delivery Box transfers from the Seller directly to the Buyer; no middleman involved.

VMM – From Me to You

The foundation principle behind VMM is the idea that products are delivered directly from the Seller to the Buyer. They do not stop and hang out for a bit inside another object (such as a Magic Box), nor do they get transferred to some virtual Avatar Account (Marketplace Linden). When a Customer makes a purchase, Viewer-Managed Marketplace takes a copy of the entire Product Folder directly from your Inventory and puts it directly into the Customer’s Inventory. For No Copy items, the transfer is a “Give” and not a “Copy”, but otherwise it is exactly the same.

More important it is exactly the same as if I handed you the entire Product Folder while standing face to face In-World. This not only simplifies the actual transfer process, it also makes it much easier to understand how it really works. Thinking of it as a face-to-face transfer makes using it that much easier too.

Long Live the Product Delivery Box

One of the features added by Direct Delivery was the ability to organize your Product Folder into many different sub-folders. It also complicated the upload process but was such a popular feature that many Merchants immediately began using sub-folders to better arrange their product’s contents. This feature was removed by VMM.

VMM is basically like me handing you an Object. Just like any other Object, the stuff inside can only have one level; it cannot contain folders that themselves contain other objects or folders. In order to solve the problems with No Copy items, they had to go back to this single-level arrangement. Basically they eliminated the roadblock that kept them from making Direct Delivery fully functional. Bravo!

Object Oriented Thinking

Which brings us to the most important point about VMM: Think of each product on the Marketplace as being contained in an old-fashioned Product Delivery Box. That means you should:

  • Organize Product Folders exactly as if each were a single In-World Object (Product Delivery Box)
  • Move or Copy Product Folders to the new Marketplace Listings window as you would put them inside another In-World Object (Product Storage Locker)
  • Update and manage the Marketplace Listings just like you would manage the contents of a Product Storage Locker

Pop Quiz: Did you notice that Marketplace Listings functions a lot like a Magic Box? Give yourself 10 points if you did.

But You Don’t Have To …

To their credit, the Marketplace Dev Team did not limit you to using the Marketplace Listings and VMM feature in only this way. In fact it is much more flexible. You can easily take out a single item, replace it with a new one, add new items … just generally mess around with the contents of Marketplace Listings. Just like most any other folder within your Inventory, you have almost the same flexibility to manage, arrange and totally screw things up.

However, it’s that last phrase that causes me to recommend thinking and working with it only in an (In-World) Object Oriented manner. Each time you make a change in the Marketplace Listings window, it causes a long chain of knock-on effects. Those effects happen only inside computers and databases, but that doesn’t guarantee perfection every time. If you start dragging bunches of items back and forth between Inventory and Marketplace Listings, you are asking the system to make lots of changes, lots of times, over and over. You never know what you might accidentally trigger.

VMM Gone Wrong - Avalanche

Final Thoughts

As we have come to expect of him, Torley Linden has once again produced an excellent series of videos about VMM. I strongly recommend you put on a fresh cup of coffee and spend some time watching them. I’ll put the first one here; you can follow it to find the rest.

You will also find some helpful resources by exploring the Second Life Blogs and Knowledge Base:


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