Last month, Amazon informed that "throughout December customers purchased well over 1 million Kindle devices per week." However, according to a Morgan Keegan analyst, Amazon may have sold close to 4 to 5 million units this holiday season. It brought the sales of iPad by 1 to 2 million.

Apple, known for its simplicity in product line, has to deal with the newest competitor as Kindle Fire defines simplicity and sleekness to the core. Comparing Kindle Fire sales with iPad in the market shows why the former has caught everyone's attention. The Amazon tablet serves its market segment with useful applications, design, usage and affordability factor.

Amazon has taken its time effectively rolling out a device which cannot replace iPad but surely can steal the show from Apple's tablet. Amazon Kindle Fire has accomplished in weeks what RIM PlayBook couldn't do over the months.

Here is a look at how Kindle Fire, the first tablet, is proving to be a serious threat to Apple iPad.

Recognized Brand: Amazon is a well-recognised brand all over the world similar to Apple. Its popularity is equals to that of Apple, Samsung and Dell. But when it comes to online retail experience, it even bests Apple's popularity.

With best services, Amazon has quietly brought out a product that can uphold its market with consumers.

Excellent Sales Strategy: With amazing line of digital contents, Amazon has adopted a tablet device which in turn will not only help the company make money by selling the digital contents but also will provide the consumers the best shopping experience. The tablet will become a good source for consumers to avail the best offer on all its line of products. It outdoes Apple iPad in this aspect.

Huge User Account Base: Amazon's active user base (close to 144 million active accounts) is expected to increase with the inclusion of the tablet. Many new consumers may go in for the affordable tablet which can provide one of the best retail experiences.

The consumers know that Kindle Fire is unlikely to bear any resemblance to the Galaxy Tabs, Flyers and Xooms out there and it is tightly integrated with Amazon's services and products. This will be a bad news for Apple.

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Moreover, consumers can use one account for everything, including apps, books, music and video stores through Amazon.

Price: One of the best reasons why Amazon Kindle Fire sales rocks is due to its pricing factor. The cheapest iPad is priced at $499 while Kindle Fire is priced at $199 which is less than half that of iPad. It is simple economics brilliantly executed. Despite its limitations of camera and volume rocker, the tablet is priced rightly.

Apart from Apple backing up iPad in content and clout, Amazon will only be the other company which enjoys a similar platform. Other companies only have tablets but have to depend on other services to get their tablets running.

Amazon has not added any additional hardware distributions found in other Android tablets, but has precisely brought a tablet device for its own segment. If all the high end hardware mattered, then other Android tablets would have made it big too.

Content and Products: The major selling point for Apple is its digital content which comes in tune with its device. Although Apple iPad is the king of apps, yet Kindle Fire bests it considerably by volume of content. Through Kindle Fire, consumers can access more than 18 million movies, TV shows, songs, magazines and books already available on Amazon's easy to browse virtual shelves.

Amazon's website offers what is probably an unmatched online shopping experience, given its breadth of product categories, shopping suggestions based on a customer's prior purchases, product rankings based on a scalable list of criteria, buyers' objective product reviews, competition among vendors and shipping options.

Amazon's advantage over Apple iPad comes in the form of default digital book store. Amazon tablet will have the appeal of the Kindle and will communicate much more effectively as a better ebook reader too. If you enjoy books, then Android Kindle has an edge over iPad.

Most of the songs available on Amazon.com are priced at $0.99 compared to $1.29 on Apple iTunes.

Ecosystem: Amazon's well-established ordering inventory management and delivery network along with services ecosystem could become as important as the Apple Store experience. User experience is not limited to device functionality. One of the reasons Apple has such a success with the iPad is due to the end-to-end user experience, particularly for non-technical customers.

Apple has also worked to develop a vast ecosystem of content and this is the key area where Amazon can differentiate itself from the rest of the hunting pack.

The e-commerce giant has long been synonymous with online shopping, content and services. Much like Apple, Amazon has felt its own strength by putting booksellers out of business and becoming the go-to place for shoppers who want to buy just about anything.

Size and Weight: Compared to 10-inch iPad, Kindle Fire is smaller at 7-inch. But much like earlier version of Kindle reader, the tablet can be held in one hand, it is lighter than iPad and a lot more portable. Amazon has played it safe when it comes to screen size as they stuck with its experience in e-readers.

Best Online Retailer: Amazon is the world's largest online retailer and is considered to be the best online Internet retailer according Foresee. What is impressive is that Amazon.com has created its stellar reputation for customer satisfaction largely without any direct human customer contact.

Amazon provides accurate information on the retail website, and content is always fresh and user friendly. Technical elements of the website functions properly and gives the Internet shoppers everything they need to make a buying decision without any human intervention or interaction.

Storage: Unlimited cloud storage is offered by Amazon while iCloud service is limited to capacity storage. Amazon will also provide safety net in case the user's stored media is lost. The provision for free storage is so enticing that it holds the first position for digital bookstore and second for mp3 store (after Apple). Also, there is about 6 gigs of free space on the Fire.

New Android Interface: Kindle Fire is running on customised Android 2.3 Gingerbread OS. Although that platform can't compete on the same level as iOS, it's getting closer as Google offers more updates.

Many people, who have used the tablet-friendly Android version, are somewhat happy with it. As Android improves over the next several months, Amazon should be able to capitalise on that with its tablet.

In fact, other Android tablets suffer from software updates which are mostly controlled by the manufacturers who often try to sell new devices with the new software instead of updating older devices with it. However, such issues are unlikely to surface on Kindle Fire, simply because Amazon has totally reworked the interface -- the device does not behave like other Android devices. Hence, users are not really going to be thinking of it as one and will not be looking for an update.

Flash: Flash is essential as many websites depend on it and also Flash enriches their web experience.

Amazon Prime: Amazon Prime membership also provides instant streaming of movies and TV shows at no additional cost. Also Amazon Prime is being offered free for a month when you purchase Kindle Fire.

Prime members have access to the Kindle Owners' Lending Library, which allows users to borrow certain popular titles for free, up to one book a month, with no due date. Also the members can elect for "No Rush" shipping, and receive a $1.00 Amazon MP3 credit in their account for each order that is not shipped via 1- or 2-day delivery.