Earlier quoted context omitted.
Here: http://maf.mozdev.org/ MAFF is a single-file format that contains one or more web pages. * Save disk space, since MAFF is based on ZIP * Include video and audio, WebM, Vorbis, Theora and more * Be universal, compatible with Linux and other platforms * Use an open format, with no risk of vendor lock-in
Wasn't there a Firefox extension that would save every single page you visited? Disk space is cheap and plentiful now, no reason not to.
A proxy server, such as RabbIT or scache or the OWASP ones, etc, will accomplish that goal without requiring an extension to any browser.
However, I disagree with your premise. Sturgeon's Law applies here: 90% of everything is crud. I can barely remember any of the websites I visited today, let alone any reason why I would want to revisit them.