One big advantage a web site has over commercial software is ease of update. You don’t have to re-burn CDs, create patches or distribute vast amounts of software updates to your end users. You update your web site once and every user from then on is served the new content.
From the viewpoint of an archivist however this ephemerality is a major problem. It is very difficult to find out what a particular news site looked like at a specific point on a specific day. Projects like the Wayback Machine have made valiant efforts to archive the web there are many sites that just change too quickly to track it all.
Zoetrope is a research project currently being developed at Adobe which aims to offer temporal browsing of web pages. Although details on the archival process are sketchy the video below shows the power of temporal browsing. For example content changes can be scrubbed using a timeline. Sections of pages and even individual data sources can be linked, compared and visualised over time. This looks like a really exciting project and as I understand there will be a temporal markup language and API.
via MIT Technology Review