Enter Instapaper, which describes itself as "a simple tool to save web pages for reading later." Instapaper works in the browser, but it also works on the iPad and the Kindle, which means that I always have access to the articles (if I remember to sync Instapaper on the iPad). This ensures that I have plenty of reading material even at 30,000 feet. Instapaper is easy to use and you can install a scriptlet called the Read Later bookmarklet on your browser that saves the web page. Installing the bookmarklet on Safari on the iPad is a little more involved, but the process is documented here. The other really great thing about Instapaper is that the bookmarklet function (i.e. Read Later) is integrated in many other applications such as RSS readers and twitter clients. That means you never have to leave your current stream of work to throw another article on the pile.
The one short coming is that Instapaper does not support pdfs which academic journals and research white papers seem to favor. Fortunately, iBooks recently added pdf support. I add pdfs to my book archive by downloading them to the Automatically Add to iTunes directory (/Users/
Finally, Youtube also has a lots of content where the video isn't terribly important and an mp3 works just as well. Download Helper is a a Firefox extension that can download video and convert it to other formats such as mp3. Using Downloader Helper's preferences menu, I set the download directory to the Automatically Add to iTunes directory so it's added to iTunes and loaded when the iPad is synched.
Thanks to Joel Ludwig (@joeludwig) for the twitter exchange that prompted this post.