I've been a professional editor/copywriter for over 30 years, and a QA Manager for over 10. My skills in spotting "wrong" have been honed through these experiences, but this is really something I do naturally. A gift? A curse? I know it can annoy others; sometimes it annoys me, too. A headline ticker scrolls across the page at the bottom of the TV screen and a misspelled word suddenly stands out from the rest. One of my favorite yoga mags is rife with errors: misspellings, verb/noun agreements, misplaced modifiers (oh, those are fun!), unhyphenated compound adjectives, incorrect punctuation.
I think it's genetic. My brothers are both like this, too. We humor one another with our "finds", chuckling at some of the more egregious errors, e-mailing humorous literary lapses, sometimes even toying with the source of the error (the writer) for our own amusement. (I'm not proud of that, but it can be pretty darned funny.)
Recently I spotted errors on two other Web sites and e-mailed the companies. They both thanked me. I've e-mailed Hallmark about their "Tradtional" cards. I wonder how many others have spotted the error?