The Kindle is one of the best single-use products on the market. To me, it's everything a dedicated device should be. It does one thing and excels at it. In fact, anything else the Kindle tries to do (audio, web browsing, etc) is laughably bad. One part of the Kindle that's been different than other eReaders out there was the lack of support for the common ePub file format. Now, Amazon seems to be finally adopting it. In an Amazon kind of way. Alex Cranz has more.
What this has meant in practice is that, for the last 15 years, if you wanted to put an ePub file on your Kindle E-reader, you had to first convert it, usually using the very powerful but very frustrating and ugly Calibre software. It was a fine workflow, but it has felt more and more annoying over the last few years.
Now, it will be a little easier to get an ePub on a Kindle. Amazon is going to allow you to send ePub files to your Kindle via the Send to Kindle function, and it should then convert the ePub into a KF8 file. Which, while technically an ePub is not really an ePub because it is only supported by Kindles.The Verge
Why Amazon makes it so cumbersome to do this is a mystery. I suspect it has to do with the fact that they're easily the market leader and have never had a major misstep with the Kindle hardware. Kobo has really come up quick to release well-reviewed readers, so it behooves Amazon to keep improving the device and offerings of Kindle. Maybe one day, there can finally be one file format to rule them all.