CAPTCHAs, where humans distill words from squiggles, hold line in spam war
Every web user has come across CAPTCHAs: wavy-lettered depiction of words you must retype as text. Most pay them no mind, but, Lev Grossman writes in Time
, we should reflect upon completing one. They're one of the rare visible skirmishes in the largely invisible war between spammers and security programmers....