I have just added a reCAPTCHA test to the site for comment submissions which makes it more difficult for spammers and the like using scripts to spam sites like this as it asks for some human interaction to confirm a visual or audile prompt.
The reCAPTCHA system gains benefits for society by using the interaction to help confirm words from old books that have been scanned in but which could not be interpreted by OCR (optical character recognition) technology. You are asked to confirm a word the system already knows and one that had scanning problems. If you know the one the system knows you are probably a reliable source to help interpret the word the system does not know. Of course, the system uses more than the input of one person to determine what the problem word is.
So, even though it is a bit of a pain to have to answer the test to post a comment, consider that you are both protecting this site and helping society in general.
You can learn more on the reCAPTCHA website.