by Simon Brew

With over $107 billion in annual revenue in 2015 (yep, that's not a typo), Amazon is the dominant online retailer on Planet Earth. What's more, its tentacles stretch farther than you might realize. Here are just a few of the companies that operate under the Amazon umbrella:

1. IMDB.COM

Amazon bought the Internet Movie Database back in 1998. Individual pages within the database now have the option to click to buy a DVD or Blu-ray of the film from Amazon. Other than that, it's remained a relatively separate entity since the purchase.

2. ALEXA.COM

Not to be confused with Amazon's digital assistant with the same name, Alexa is an analytics provider. Thus, it's used primarily to rank the popularity of websites. Amazon snapped up the service in 1999, in a deal worth $250 million in stock.

3. AUDIBLE

Arguably the most popular repository of audiobooks online, Audible became part of the Amazon empire back in 2008 in a deal that cost Amazon $300 million. Now, when you search for a book on Amazon, you have the option to purchase the Audible narration along with your Kindle e-book at a reduced price; and Amazon Prime members have access to original audio series created by Audible.

4. BOX OFFICE MOJO

The website Box Office Mojo has been charting the box office performance of movies since 1999, and in July 2008, IMDb (which, we've discussed, is owned by Amazon) bought the service. Thus far, Box Office Mojo has continued to run as its own entity, although in October 2014, traffic for one day was redirected to IMDb's own box office page. This change was reversed within 24 hours, but it's added a question mark to the future of the site.

5. ABEBOOKS

Acquired by Amazon in 2008, AbeBooks was and is a site dedicated to tracking down rare, used and out of print books. It works with independent bookstores to ensure a hefty range of titles that otherwise would be hard to find.

6. ZAPPOS

If you've ever debated the merits of Zappos over Amazon, we've got some bad news for you: Amazon bought the shoe retailer in 2009 for a whopping $807 million. Since its acquisition, Zappos has remained an independent entity and has worked hard to maintain its individual company culture and values.

7. GOODREADS

One of the 350 most popular websites in the world (according to Alexa, at least!), Goodreads is a community of book reviews, recommendations, and discussion. It came to life in December 2006, and was acquired by Amazon in March 2013. While it was a pretty logical purchase for the company, many Goodreads devotees were angered by it because they believed the Amazon affiliation would harm local booksellers (Goodreads users would now be prompted to purchase the books from Amazon, rather than mom-and-pop shops).

8. DOUBLE HELIX GAMES

Amazon has snapped up a couple of video game developers throughout its history, including Double Helix Games in 2014. The studio is best known for creating titles such as Killer Instinct and Silent Hill: Homecoming.

9. TWITCH

The live video-game streaming platform was snapped up by Amazon in the autumn of 2014 for a cool $970 million, and now, access to Twitch is free with a Prime membership. Google had been circling Twitch beforehand, but it was Amazon that ultimately concluded the deal. Why would a business that is primarily a retailer want a live-streaming service? Business Insider's Matt Weinberger believes the acquisition was a way for Amazon to bolster its Amazon Web Serves division, which focuses on cloud computing.

10. SHOPBOP

Trendsetters are likely familiar with the shopping site, which was founded in 2000 and bought by Amazon in 2006. Thanks to the partnership, Shopbop purchases are eligible for Amazon Prime's free two-day shipping.

11. QUIDSI

Quidsi might not be a household name, but you've probably heard of (and use) its sites, which include Wag.com (pet supplies), Soap.com (household needs), Diapers.com (baby supplies), and BeautyBar.com (cosmetics). Amazon made Quidsi part of its family in 2010 for $500 million.