As web archives mature and expand, a growing question revolves around the role of these archives in society. What should their primary mission(s) be and how can they best fulfill those roles? At their most basic level, I believe web archives fulfill three primary roles: Preservation, Research, and Authentication, in that order.
• Preservation. First and foremost, web archives preserve the web. They act as the web equivalent of the archive or library, constantly monitoring for new content, requesting a copy of that content, and keeping a copy of it for posterity. In this role, their mission is to acquire and preserve the web for future generations, with access being primarily through basic browsing and retrieval. Some archives, for legal purposes, may not even be able to provide access to their holdings during the lifetime of the organizations providing them content, instead holding that material under embargo for a certain number of years, but ensuring its continued survival for future generations.
See on blogs.loc.gov