Wired Editor Chris Anderson’s Long Tail is an important book. The Long Tail provides the best description for the Infinite Inventory world our e-commerce web sites inherit. Inventory is slouching toward infinity because adding a digital product page costs pennies and may yield dollars. Amazon.com understands Infinite Inventory and its implications. Amazon wants to sell every book ever published and they accomplish this goal with vast distribution centers (warehouses) and the Amazon Partner Network.
The Amazon Partner Network provides important information on Stock Keeping Units (SKU’s) Amazon doesn’t inventory (i.e. include in their warehouse). If Amazon sees a pop for a product they don’t currently inventory it is easy enough to buy the suddenly popular product and move the sale from a partner to Amazon. If this sounds like partners beware you are not wrong. An Amazon partner selling rare out-of-print books has nothing to worry about. Amazon doesn’t want to inventory something as arcane as out-of-print books, but why not make a little money moving, or arbitraging, web traffic over to a partner. Amazon partner’s selling potentially popular products should beware. Once a product achieves a magical level of traffic or “sales intent” Amazon’s algorithm’s will kick in and they will be selling the thing faster than you can say Google.
These two concepts – Infinite Inventory and The Long Tail – are related and creations of our new digital marketing world. Before the Internet shelf space acted as a governor, physical shelf space was the ultimate filter keeping number of SKU’s down. Building Walmart and Target Super Stores with over 100,000 SKU’s under a single large roof was the first hint at a new Infinite Inventory world. Even in these behemoth stores physical limitations curb product presentation. The web eliminates physical restraint. Almost ten years ago I attended a conference where Barnes and Noble discussed having over a million SKU’s in stock, in their warehouse.
Barnes & Noble helped me realize products were functioning as something other than physical things. Our brave new digital world was transforming products from material things to information. Information is cheap to manage and, thanks to Moore’s Law, always getting cheaper. In an Infinite Inventory world it makes sense to “sell” every SKU in your market segment. “Sell” in quotes because physical inventory costs money, much more money than digital inventory. It makes sense to “sell” every widget in your market, but it may not make sense to inventory every product. This is where a partner network comes in handy.
Amazon understands the value of being listed in search engines for every book on the planet is greater, far greater, than the cost of having an Amazon employee create a product page and let the brilliant user generated content (reviews, comments from publishers) make the page highly relevant for search engine algorithms and consumers. Amazon functions as search engine AND merchant because Jeff Bezos understands Infinite Inventory and Anderson’s Long Tail.
Seeing Anderson’s Long Tail
During my tenure as an E-Commerce Director I saw Anderson’s Long Tail as a repeatable fractal. No matter how I cut our sales data I saw a long tail distribution. Another name for The Long Tail is the 80/20 rule. Most of your site’s business will be generated by 20% (or less) of your company’s SKU’s. Sales represent the ultimate vote. Traffic, reviews and comments are good, but nothing counts as much as people voting with their wallet.
Understanding those votes, encouraging and nourishing sales requires knowing your company’s 80/20 split. Here is a step-by-step method to calculate Anderson’s Long Tail, the 80/20 rule, in your site’s sales numbers using fictional data:
- Pull a report of sales by SKU (or name as in the example below) over some period of time.
- Total your sales (sum the column).
- Create a new column to figure out what % of the total each SKU contributes by dividing the SKU’s sales by the total (see % total column).
- Create a new column to calculate the running % by adding each % to each other (adding %’s is normally a bad idea, but we are just using the calculation as a yardstick to see where the 80/20 rule splits sales).
- When your “Running %” reaches 80% anything about the line is contributing 80% of your sales.
When you know your 80/20 split you may be tempted to ignore the other items. Don’t ignore any item making you money. Don’t even ignore the products NOT making you money. The web works in a magical synergy where everything matters. In my last position the 20% left over after figuring our 80% contributed over a million dollars in sales! The 20% is dancing with your best sellers. You never know when a new wave may vault some small product back into the “head” of your sales chart. Maybe a tribe forms around “Dog Pencils” and they become all the rage more than doubling sales. Even if such a thing will NEVER happen the 20% still represent important contributions.
Even products you carry but aren’t selling can be important to the spaghetti that is Google and Search Engine Marketing. The first rule of Search Engine Optimization is DO NO HARM. If your company moves inventory in and out taking down product pages even as you put up new ones then your IT department is doing harm. You may be trimming product pages and products that provide valuable links, traffic and sales to other products. Google’s memory is forever, so any change to your product page presentation changes Google’s perception of your site and violates the first rule of Search Engine Marketing (SEM) – DO NO HARM.
Hope this post helps you see Anderson’s Long Tail in your numbers and begin to understand the implications of Infinite Inventory.
| Products | $ Sales | % Total | Running % |
| Balloon Dog | $30,455 | 32.73% | 32.73% |
| Holzer LED | $24,000 | 25.79% | 58.53% |
| Bullman Pics | $20,000 | 21.49% | 80.02% |
| Smith Sculp | $8,000 | 8.60% | 88.62% |
| Acme Bag | $5,000 | 5.37% | 93.99% |
| Art Paper | $2,300 | 2.47% | 96.46% |
| Art Cards | $1,100 | 1.18% | 97.65% |
| Art Jackets | $800 | 0.86% | 98.51% |
| P Napkins | $500 | 0.54% | 99.04% |
| De K Cups | $300 | 0.32% | 99.37% |
| Koons Puppy | $200 | 0.21% | 99.58% |
| Martin Dogs | $100 | 0.11% | 99.69% |
| Dog Pencils | $100 | 0.11% | 99.80% |
| Cat bowl | $65 | 0.07% | 99.87% |
| Art Journal | $50 | 0.05% | 99.92% |
| Frida CD | $45 | 0.05% | 99.97% |
| Mzx Radio | $30 | 0.03% | 100.00% |
| $93,045 | |||







