Amazon. With a massive 59 million active customers and more than 42 terabytes of data, it’s Amazon that races itself to the number 8th spot in our top 10 databases. World’s largest retail store, Amazon has huge collection of data that includes general information like phone number and address to receipts and wishlists and any sort of data that the website can extract from its users as they are logged on. It’s said that Amazon has a mass collection of 250,000 full text books which are available online. No wonder Amazon is considered as the world’s largest online community as users can interact and comment virtually on every page of this website.