A brief trip to the AmazonSupply site reveals that it's definitely not ready for prime time. After doing an initial search, a somewhat random selection of products in the category were displayed. But whenever I clicked through to the detail page, I got an error that the page did not exist.

Also, there was one really hilarious whopper in the story that deserves some attention:

"If there’s one company standing in Amazon’s way, it’s Chicago-based industrial supplies giant W.W. Grainger. With $9.4 billion in revenues it’s definitely the business to beat, controlling an estimated 6% of the entire B2B market. With a robust e-commerce operation."

While Grainger is a serious competitor, their actual competitive advantage is that they have numerous local outlets that you can actually visit. If the local store doesn't have something, they'll send it to your local store at no charge.

With that said, Grainger's site isn't particularly great, although visiting it just now, it seems they may have improved the usability a bit. I'd hardly characterize it as a "robust e-commerce operation."

The real competitor, at least on the web, is McMaster-Carr. Their product selection is vast; their prices are usually better than Grainger; their delivery is incredibly speedy, with orders typically arriving the next day, even with standard shipping. On top of that, their site is amazingly good for drilling down and finding exactly what you need.