[EDITED]for those who thought designing a bot-check is easy (in Off-topic)

We haven't had one in a while, but it used to be a fairly regular occurrence that someone would say, "bot checks are too hard! why don't you do [easily defeated bot check] instead?"

This page lists a bunch of such easily-defeated checks. (story now contains no reminder of the guy's bottom)

I was going to bring the up earlier, but I didn't want to start the whole discussion.

Oddly, pay pal's is not very strong.

non pg link....if you look at one sites idea for botcheck...its its ...that guy doing that thing with his bottom :(

Eww, Gross.

Why isn't CB bot checks in there? :)

Why tempt fate?

I was going to ask the same thing, how come the glorious CB bot check isn't listed there?

That site is about CAPTCHA checks, which CB bot checks aren't.

completely automated public Turing test to tell computers and humans apart.

so something to let a human pass but stump a computer...that sounds like a botcheck.

What makes Jonathan's bot check extra difficult is the script and merging of lines. The site is a fascinating read especially that piece on how one guy created a program to defeat a CAPTCHA.

among the things that make jonathans bot checks so hard for computer scripts is that they can recognize letters and words but have extreme difficulties with the overlapping of them.

but if you go and analyse the CB bot checks then you can also come up with some weaknesses:

almost constant font (though with this comes a change in size and tilting)
low rotation (though font is tilted often)
no color variation
weak deformation (though overlapping could mean the same)

but also strong points:

change in font sizes and style (sort of)
strong perturbation (caused by overlapping)
overlapping words / sort of deformation
tilting words
large dictionary

amongst our weaponry are such diverse elements as:
- fear
- overlapping letters
- a fanatical devotion to vocabulary

A typeface in a different size *is* a different font, so the botcheck uses lots of different fonts...

that was the explanation i was looking for bartjan :)