I'm curious: what method specifically are you referring to? I've seen talks on getting through Google's new NoCatpcha Recaptcha a small percentage of the time (which is worrying but nowhere near as troubling as the susceptibility to OCR most other captchas suffer from) but I wasn't aware of any reliable and automated way to bypass it (since outsourcing them to human captcha solvers via a paid (~2 bucks per 1k captchas) API isn't exactly automated).
I was being purposely vague. However, there's a method of automatically downloading the sound files when requesting for a audio version rather than the images to help with usually impaired people. Generally, people write a Python script, automatically download it, and then can input it. I haven't tried this myself, but have seen it working on a test site from a friend of mine. He kept on having bots sign up to his website out of nowhere, and he found that this was the method they were using.
Obviously, I haven't checked whether this can be done on Bitcointalk, because I haven't logged out in a few months. But, it shouldn't be any different to what I witnessed a few months ago.
I think the letter puzzles have an 80% solve rate when ran through several OCR cloud-products. There was a rather interesting paper I read about the bypass.
I've used deathbycaptcha before, and it's a pretty decent service. It provides an API, which makes it
automated.