Comments regarding this (from the wiki):
* By fostering a community, the division between content production and content acquisition could be reduced: "Report a typo" on the book display page would encourage a user, perhaps, to think about contributing on a larger scale (for example, by proofing a page).
Jim Tinsely, who has dealt with making corrections to PG texts for years, and at the present deals with most of the emails sent to the PG "errata" list, has reported that "about half" of the submitted "corrections" are actually right in the etext. That is, the e-text itself correctly represents the original, and the suggested correction is in error.
There are apparently some spots in Mark Twain's writing which were intentionally misspelled by the author for the effect in the story, and which are regularly reported as "errors".
Also, sometimes people will try to "fix" older spellings of words such as Tokio--Tokyo; shew--show; fyle--file; etc.
It takes a very patient volunteer to work through these suggested corrections, go about fixing those that are obvious, send messages back saying "thanks for your help, but..." for those mentioned above, and do further investigation/guessing for those in a grey area.
This shows the need and the benefit of having the original page scans available to readers so those who submit errata can first check with the original. Jon