Theresa Knott wrote:
ASCII paswwords?
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Theresa
Alas, they won't work for the blind either.
Oh, and there's one more problem with textual captchas: you will also
need them to be available in every language, which implies a non-trivial
translation effort.
At least the current visual captchas can be used by anyone familiar with
the Latin alphabet (although they're currently harder for non-English
speakers).
I still think the best idea is a web form where the user is required to
make their request for access in natural language using complete
sentences, possibly prompted by a set of simple questions. Real requests
should be easy for human beings to distinguish from chatbot-like
computer-generated requests, unless they are generated using canned
human-generated sentence structures, which will be easy to filter out
using a Bayesian scheme. Engaging in an arms race against this will of
course be possible, but will require significant amounts of human effort
from the spammers, which will slow them down.
Sample questions might be:
"Please tell us why you want to edit."
"Please tell us what you think of Wikipedia."
"How did you find this website?"
-- Neil