I see there is now a "Capcha" for story submissions. They are on most websites these days.

Purely as a matter of interest, what are they meant to guard against?

As I see it, if a robot was clever enough to want to submit a story to the archive it would easily be able to get past the capcha.

Robots have yet to get to that stage so presumably it's some form of virus cum spam prevention. If so how effective is it? Where do you get them from and how easy or difficult are they to put into a webpage?

Kortpeel

Its like the old cold war between America and Russia except its between thief's, spammers and criminals who want your identity and your money.

I don't know how hard it was for IE to add the script to the page, but it certainly did cut down on the number of spam ads being dumped into the story tank.

If you want to know more about captchas, just go to the main page: opencaptcha.com It mentions not only why they work, but problems that some captcha-furnishing companies have, and how opencaptcha works to solve those issues, which answers all of your questions in just a few sentences.

Robots (or crawlers or spiders or 'bots or whatever you wanna call 'em) can't understand images, which captchas are. Bots do parse text, so html source is their target. So that's why me and a lot of folk write (in text) our emails like this: "my name (at)somewhere((dot)) com because a human can decypher this but the 'bots can't. You could program 'em to, but why bother since the lowest-hanging-fruit rule applies?

Best of all, opencaptcha isn't dependent on special configurations, etc. and is free for use, unlike solutions from some companies pushing captcha use.