NetXtreme/AspXtreme CAPTCHA is Lanapsoft's BotDetect ASP.NET CAPTCHA rip-off based on a decompiled BotDetect CAPTCHA source code. Unlike original, AspXtreme CAPTCHA lacks a few features that 'the vendor' couldn't figure out, and is enhanced with multiple bugs not present in the original version. Stay away from it.

More about this particular rip-off, as well as about numerous other rip-offs done by the same 'vendor' with an ever changing name/brand and URL you can find at http://cheated.by.safabyte.net/.

Some folks find weird ways for making money.

aiCaptcha is an excellent and easy to read article that includes a step by step guide on breaking of a particular weak captcha with some serious stuff — but without any rocket science involved in the process. And exactly because of that lack of rocket science aiCaptcha is a must read for anyone thinking about deploying captchas.

Even if you are not going to understand just about everything that is written in the article, aiCaptcha will make you able to recognize a lot of weaknesses in algorithms of many captchas that are available on the market today. In turn, you will be able to avoid deploying those weak captchas on your website.

aiCaptcha source code and executables are not available to the public.

The long-term status of Captcha Killer is a bit unclear at this moment.

While the CaptchaKiller website does not state anywhere that the Captcha Killer is, or will be, out of business — the guy's post made 2007/09/24 clearly states:

"I'm facing legal trouble in the US. Can someone please help me move this company offshore? Any tips? Who should I be talking to?"

It seems that Captcha Killer got at least the MySpace legal team on its back and is now thinking about relocation. According to another post, the most likely destination is Panama.

Unfortunately, Captcha Killer says nothing about their captcha breaking technology :(

CaptchaSolver seems not to exist any more. The website is down, and we do not think that we are going to hear about it again. At present, it is listed here only because of historical reasons.

CaptchaSolver used to be captcha-breaking sweat-shop. Numerous download sites still list CaptchaSolver API among their entries — but the download links lead to nowhere.

Hopefully, there will be someone out there who still has a copy of CaptchaSolver API. And if he/she is willing to forward it to captcha.org editors — in the future the CaptchaSolver entry might also get some educational reasons for its existence, beside the historical ones.

Google27 is just another of those shady captcha-breaking sweat-shop entities that claim to provide the dark-side with a technology and low-cost labor needed for bypassing captchas on high-value-target websites such are MySpace and Yahoo.

Google27 claims they will do, as a professional service, all the integration work between your existing bot software and their captcha-entry agents.

Google27 website seems to be banned from Google index so we are not providing a direct link to it. Use copy/paste instead. We simply do not want to take the risk and make Google algorithms nervous about our site as well. Ironically, it seems that Google does not ban Google27 from AdWords :)

According to the PWNTCHA website PWNTCHA is 'simply a toolkit of image manipulation functions, and a list of known CAPTCHAs with the associated list of image operations to apply in order to decode each of them.'

So far we were unable to find the specifications of the PWNTCHA "toolkit". Also, we were unable to find PWNTCHA's "associated list of image operations to apply in order to decode each of them." Maybe we were looking on all the wrong places. Who knows.

If we were able to find those missing parts we would recommend PWNTCHA as a something that one interested in captchas should read. This way, there is really nothing to recommend.

PWNTCHA source code and executables are also not available to the public.

Akismet might be an interesting captcha alternative for those folks to whom comment spam is the only problem caused by bots.

Technologically, Akismet is based on some form of automated spam-filtering. The self-correction of algorithms is made possible by the feedback that is constantly flowing-in through the built-in collaborative component.

If you are member of the above-mentioned group, and the web side of your business can survive some false positives and negatives that will inevitably keep happening forever as a result of Akismet's technological foundation, it might be worth to give Akismet a try.

While Akismet will not solve your spam problems, it will make living with them much easier.