Here is the short version:
reCAPTCHA protects e-mail addresses. Post your customized reCAPTCHA link instead of plain text e-mail address and bottom-feeding spammers won't harvest it and SPAM you. But wait there is more...
Everyone who has ever dealt with OCR (optical character recognition) knows the failing of the technology - machines just cannot recognize some characters or words. reCAPTCHA has married the failing of OCR with the need for cyber-security. When you decypher a reCAPTCHA you are actually contributing to the OCRing of books by a Carnegie Mellon University project.
I am going to vote for Barack Obama.
I am William "Papa" Meloney and I endorse this message.
No need for captions...