On there website: "We are currently not accepting archiving requests. The archival state/snapshots of websites that have been archived with WebCite in the past can still be accessed and cited."

And archive.vn "history" for domains broken. Other domains available @ https://en.wikipedia.org/wiki/Archive.today

(EDIT) Found three more similar sites;

  * https://yubnub.org/
  * http://itools.com/
  * http://timetravel.mementoweb.org/

Thanks for helping!