To clear up the misconception... CAPTCHA is not a thing, it's a blanket classification for a concept.
It's not possible to say "CAPTCHA has been broken!" Hehe.
Any system where you attempt to tell humans and computers apart by challenging them with some kind of interactive test is a CAPTCHA as long is it's entirely automated on your side.
Asking a math (or other type of) question is as much a CAPTCHA as distorted numbers and letters. There are endless varieties of CAPTCHA type tests.
As far as traditional image type CAPTCHAs go... The capability to write a program that can parse and interpret a graphic has been around since before the web. In that sense CAPTCHA was broken long before the acronym was coined.
If you're clever, you can write a program to break a single CAPTCHA scheme. However, that program will only break that one CAPTCHA scheme and it will have taken you a lot of time and effort to write it.
There is no program in existence that could spider the web and just break any CAPTCHA it found. There are just too many variations. The best you could do would be to create a program that can break some popular CAPTCHA implementation where a lot of webmasters have used the same code. If you were ambitious you could perhaps write something that would handle small variations (it might break all number/letter type CAPTCHAs where single color text on a single color background was used and the only obfuscation method involved warping).
Having accomplished this you would (maybe) pull off breaking 5% of the CAPTCHAs encountered, and that's probably way too high a number.
Someone posted about groups claiming to break "many" CAPTCHA systems with 80% success. What that means is that they have an app that can pass a very weak type of CAPTCHA implementation and even then still fails 20% of the time.
If a spammer did take the huge amount of time to write the above program, the weak CAPTCHA systems it was able to break would quickly change to something else and the spammer would be back to square one.
Basically, it's still safe to say that you can stop automated posting 100% with a creative CAPTCHA. :-)