One of my friends use Pocket (https://getpocket.com/) for this purpose. Firefox actually has Pocket built into the browser, which actually makes it rather convenient. I'm not sure if they have a note-taking/summary feature, though.
I've never really used it because by the time I had found out about it, I had already built something similar in the form of a webapp using Parse.
I recommend taking a look at XMLStarlet [1] (mentioned in the article as a dependency of the author's Bash library) -- it is a nice tool for manipulating XML content from the command line.
I'm wondering what the difference between this idea and instapaper is? (I don't use instapaper, but from what I've read about it I thought this is what it did?)
I have a different approach, albeit much simpler: I print stuff to PDF that I want to read later, and keep a massive, growing PDF archive that I can search with normal tools, etc. Sure, it doesn't capture all the javascript goodness .. but for most of the stuff I want to read, having PDF offline is great. I'm sort of surprised its not a more common practice, to be honest ..
I have Instapaper email 20 articles to my Kindle when it has enough new ones, I guess one could make something to download that file, or the export account file from Instapaper and processes those links, to be read by any ebook software.
I've never really used it because by the time I had found out about it, I had already built something similar in the form of a webapp using Parse.