Ebook readers are great for any kind of long(ish) form content even if that doesn't necessarily mean books. You're going to want to read a long article on your reader, or on your Kindle tablet for that matter, at your leisure rather than on your laptop.
There have been ways of getting web content onto your devices, both official and unofficial, but Amazon finally came up with something simple and practical, the Send to Kindle button.
The browser extension was first made available for Chrome users, but it is now available for Firefox as well. So if you're a Firefox user and a Kindle owner, there's now a simple and official way for you to send any page you want to read later to your device.
The feature is available on desktops as well, for Windows and Mac, but it is also included in the Android Kindle app, so you can send any file or text to your devices from your phone or tablet.
Send to Kindle for Firefox is available for download here.
Send to Kindle for Chrome is available for download here.