One of the most popular spam tools is
XRumer. From what's been said elsewhere and from what we've seen, CAPTCHAs like ReCaptcha can be cracked, either automatically (through OCR/averaging) or semi-automatically (through third parties who offer the solving of captures within seconds through APIs). Text-captchas, too, are easily cracked. From what we've seen, users of said spam tools were given credits for any solved text-captcha that is then stored in a global database. Easy permutation (simple math problems changing digits) is also solved by the tool.