If you often find online material that you want to read later, try Pocket.
The app puts a small checkmark icon next to the Chrome browser's address bar. When you click the icon, it saves the contents you're current looking at -- including images and all the text, including additional pages -- to Pocket's site and synchronizes it with your Chromebook's local storage. Later, you can read the entire document even if you're disconnected.
There are some limitations if you're reading a page offline -- for example, Pocket doesn't download videos. And while you can choose the size and color of your typeface and add tags for content, you can't create folders to organize the material. Still, it's a great way to keep up with your reading.