Theresa Knott wrote:
ASCII paswwords?
| /\ | | / \ | | /___\ | | / \ | |________ / \ |
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