Sites like Quora have excluded themselves from wayback machine. And worse, some of those sites block direct access also (Quora blocks all Tor traffic). This means users are lead on a chase for an unreachable document.

The fix: Please make the list of hosts that are excluded from the Wayback Machine (WBM) easily accessible. This would enable search engines to exclude such time-wasting sites from search results, or to at least give them a lower ranking. It would also make it possible to create browser plugins that will flag such sites in search results of mainstream search engines, so that users know to avoid them.

Excluded websites also create a problem for bloggers and journalists. We take the time to write a well-cited article, and then a link goes dead. The remedy is to substitute the dead link with a WBM-mirror, which could even be automated. But when WBM is blocked, there's no recourse. Part of our article loses credibility or becomes useless. We would rather not spend the time drafting an article that relies on such unreliable sources.

Note this enhancement is similar but complemtary to this bug: #199