I don't have the exact numbers to support or refute their claim, but I have some reasons to believe Amazon. Analysts estimate Kindle Fire sales to be in order of 6MM in its first quarter. (Source:) This is a big number, and I think captures a big part of this number. Here are my reasons for this:
- Dual role: Manufacturer & Online stores: For most other electronics goods, you can expect the Online sales to be split across manufacturers' websites and other online stores. In case of Kindle Fire, Amazon is both the manufacturer and a leading online store. Also, since Amazon offers free shipping for Kindle Fire even for non-prime members and no other online store offers a lower price, there is no reason to buy from anywhere else, if you are ordering online.
- Relatively low offline sales: I know that Kindle Fire is available in physical stores like BestBuy, but there is no major offline official channel like Apple stores for iPods/iPads, etc, or AT&T/Verizon stores for Samsung phones. So I expect the majority of sales to be from online channels, and Amazon should grab the lion's share from that.(See previous point).
- There is just one Kindle fire: Best selling products are reported at an SKU level. A variation like color or size in product will make it a different product for the purposes of best-seller rankings. For example, Kindle Fire is not competing with iPod touch, not even with iPod touch 4G. The competition is against iPod touch 4G 8GB (Black),iPod touch 4G 8GB (White) and iPod touch 4G 32GB-Black, all of which rank in Top 20 Electronics goods. As for Kindle Fire, there is just one variation of it: One size, one storage capacity (8GB), One color (Black). (Other products from Kindle family are simply book-readers, and hence, I am not clubbing them as the same product)
- Very high number of reviews: Number of reviews may not be accurate representative of actual sales, but you can easily expect the two figures to have at least a moderate correlation and it can at least give you some idea about actual units sold. Since the Fire was launched in mid-November, 2011, it has amassed close to 18,000 reviews. Most other products would be lucky to get 2000 reviews. (Sample the top sellers across few categories: Books=> Fifty shades of Gray: 1500 reviews, Apps=> Angry Birds: 965 reviews, Camera=> Canon PowerShot D10:585 reviews) Only products that I could locate having higher number of reviews was Kindle Keyboard, and that was released way back in Summer 2010! This does indicate a possibility of Kindle Fire being their top selling product.
Again, as I said, I have no numbers, but the reasons above are convincing enough for me to believe them. Will wait for Amazon to share official sales figures, which may perhaps give us a clearer idea on this.