Shelfari was a social cataloging website for books. Shelfari users built virtual bookshelves of the titles which they owned or had read and they could rate, review, tag and discuss their books. Users could also create groups that other members could join, create discussions and talk about books, or other topics. Recommendations could be sent to friends on the site for what books to read. Amazon bought the company in August 2008.[100] Shelfari continued to function as an independent book social network within the Amazon until January 2016, when Amazon announced that it would be merging Shelfari with Goodreads and closing down Shelfari.[102][103]
In 2015, Amazon surpassed Walmart as the most valuable retailer in the United States by market capitalization.[11] Amazon is the third most valuable public company in the United States (behind Apple and Microsoft),[12] the largest Internet company by revenue in the world, and after Walmart, the second largest employer in the United States.[13] In 2017, Amazon acquired Whole Foods Market for $13.4 billion, which vastly increased Amazon's presence as a brick-and-mortar retailer.[14] The acquisition was interpreted by some as a direct attempt to challenge Walmart's traditional retail stores.[15]

While sites like eBay and Craigslist allow you to list any item barring certain exceptions, Amazon asks that you find a similar product in its database. If you can’t find a similar product, Amazon has a procedure for creating a new product page. You should be aware, however, that new products often require additional approval from Amazon before listing can occur.

The company has also invested in a number of growing firms, both in the United States and Internationally.[67][68] In 2014, Amazon purchased top level domain .buy in auction for over $4 million.[69][70] The company has invested in brands that offer a wide range of services and products, including Engine Yard, a Ruby-on-Rails platform as a service company,[71] and Living Social, a local deal site.[72]
Although As Seen On TV was founded in the 1980’s by Shark Tank panel member Kevin Harrington, the public domain label is often used to refer to all infomercials that have aired to date – ranging from the familiar Ron Popeil and his line of popular “o-matic” products, to Sir James Dyson and everyone in between. The infomercials all use direct marketing which allows customers to immediately understand the benefits of a product, and provides the seller with an easy way to track results and understand if a campaign will be profitable.