put up that warning on their own website:

"This site may harm your computer."

:P

Instead of using arcane captchas, why not use logic for validation instead? ie. "spell the second day of the week", or "spell the number seven"...

Seems to me that it would be almost impossible for an automated system to solve logic codes...

The Logic questions proposed are a good suggestion, with one major flaw, limit of questions. CAPTCHA has a nearly unlimited number of possibilities if randomly generated (only limited by number of characters in the string). Where questions have to be human-generated (or mostly human generated with maybe a small random component), so there is a very finite limit of possibilities. A human also has to enter the result, so there is a sanity limit involved as well (e.g. Spell the number 1,234,567,890 = One billion, two hundred and thirty-four million...).

In any cryptographic or security field, it is always a back-and-forth between the good guys and bad guys (we secure it, they crack it, we fix it, they find another hole...), but it sounds like Yahoo has given up the battle. There needs to be enough pressure for these companies to research something new to keep the baddies at bay a little longer.

Sadly, the only reason spammers are still in business (and thus keep working at this), is that people buy the crap they sell. If people would stop buying the fake Viagra and dubious "enlargement" products, the spammers would stop (no money, no point).

Google and friends (and here they are all friends against a common enemy) should stop preventing spam altogether, and leave spam flow free for a while, until enough people are fed up and some law is created and some law enforcement is made against spam and especially spammers.

Adding to Dave's idea that instead of random jibrish captcha should validate graphicly altered logic questions