Dear all, We are delighted to be able to announce the availability of the beta Memento extension for Chrome. The extension is available in the Chrome store: https://chrome.google.com/webstore/detail/memento/jgbfpjledahoajcppakbgilmojkaghgm?hl=en&gl=US Below, we include the description that accompanies the extension in the Chrome store, which highlights its web time travel and 404-circumventing features. Your feedback would be much appreciated to help us get it ready for prime time. We would like to take this opportunity to thank: - Harihar Shankar for the effort he invested in developing the extension. - Luydmila Balakireva, Martin Klein, Michael Nelson, James Powell, for their input during the development process. Many thanks, Rob Sanderson and Herbert Van de Sompel, Los Alamos National Laboratory == Description Travel to the past of the web by right-clicking pages and links. Memento for Chrome allows you to seamlessly navigate between the present web and the web of the past. It turns your browser into a web time travel machine that is activated by means of a Memento sub-menu that is available on right-click. First, select a date for time travel by clicking the black Memento extension icon. Now right-click on a web page, and click the "Get near …" option from the Memento sub-menu to see what the page looked like around the selected date. Do the same for any link in a page to see what the linked page looked like. If you hit one of those nasty "Page not Found" errors, right-click and select the "Get near current time" option to see what the page looked like before it vanished from the web. When on a past version of a page - the Memento extension icon is now red - right-click the page and select the "Get current time" option to see what it looks like now. Memento for Chrome obtains prior versions of pages from web archives around the world, including the massive web-wide Internet Archive, national archives such as the British Library and UK National Archives web archives, and on-demand web archives such as archive.is. It also allows time travel in all language versions of Wikipedia. There's two things Memento for Chrome can not do for you: obtain a prior version of a page when none have been archived and time travel into the future. Our sincere apologies for that. Technically, the Memento for Chrome extension is a client-side implementation of the Memento protocol that extends HTTP with content negotiation in the date time dimension. Many web archives have implemented server-side support for the Memento protocol, and, in essence, every content management system that supports time-based versioning can implement it. Technical details are in the Memento Internet Draft at http://www.mementoweb.org/guide/rfc/ID/. General information about the protocol, including a quick introduction, is available at http://mementoweb.org.