These applications sit in your browser, and allow you to quickly archive a webpage for later reading. They clean up the webpage, removing ads and complicated scripting, so you just have the text you want to read.
You can then read the content in your browser at their sites, on a mobile phone, or on a tablet. Instapaper will also allow you to configure content collections to show up on your Kindle. Both are integrated with a great site full of longer articles, longform.org, allowing you to quickly choose some reading before you catch that plane and lose your internet connection.
In terms of genealogy, I use these tools to gather historical pieces, such as the articles the New York Times is doing on the sesquicentennial of the Civil War, “Disunion,” as well as more topical items, such as John McPhee’s 1987 New Yorker piece about the Army Corps of Engineers and its attempts to control the Mississippi River, Atchafalaya: The Control of Nature. (That was topical then, and is topical now; I found it on longform.org.)
Instapaper allows you to format the stories for printing; Read it Later has a great (and not too expensive) iPad app that automatically categorizes the content. I find Read it Later’s web interface to be more attractive, but some of the features of Instapaper to be more compelling, including Readability integration and Kindle auto-delivery.
I’m not sure which one of these I will choose yet, but I know I will have a lot of reading at hand.…
Another site to note is Readability, which is free for simple cleanup of pages you come across, but costs $5 (or more if you decide to make a donation) if you want to save them for later. 70% of the proceeds are provided to the authors and publishers of the content.