I have just recently started using "Scrapbook Plus," a Firefox add-on. You just right-click the page you are on and it's saved. Free at https://addons.mozilla.org/firefox/addon/8186
I make .PDF files out of the threads I wish to keep...of course, I've never gone back and opened a single one of those files in five years on being here...
predominately some of my own in an email to myself and save it on a file on my AOL. That works well as it's quick and easy. I have also saved whole threads the same way.