So with all these problems, all these new ways to attack users both by e-mail and on social networks and blogs, is there any hope for CAPTCHA?

No, not really.

"I think my view on this now is that time is definitely running out for current CAPTCHA systems; already they are not as effective as they once were," says Wood. "It's already becoming more difficult for real customers to use them successfully, and they continue to come under increasing pressure from spammers."

Chenette goes further: "CAPTCHA has been broken for the last year and a half. The technology has really not progressed. They've got a little bit harder but the hackers have made programs that can easily break them. This works both with print and audio CAPTCHA. All of these have been broken in one way or the other."

Chenette says it's a "fundamental problem with no simple answer." After all, "harder CAPTCHA solutions mean harder problems for people as well." And he believes that "the idea behind CAPTCHA may need to be part of a solution."

Chenette doesn't expect that a one-size-fits-all solution will emerge, however. "Each site will have to choose its own answer. Financial sector sites, for example, will be more difficult than a free social-networking site," he notes.

Wood expects to see CAPTCHA replaced soon. "I would expect to see some sites introducing new techniques to replace the existing CAPTCHA models, maybe as early as the beginning of next year, perhaps involving 3-D spatial perception, such as the one created by SpamFizzle," he says.

And if that fails in its turn, well, there's always CAPTCHAs like the one used by Quantum Random Bit Generator Service. You do know your math through at least calculus ... right?