Mark Zuckerberg is one of the most powerful men in the world becausebillions of people give Facebook, which he founded, free access to their personal data. In return, users receive carefully curated snapshots of his life: baby photos, mundane office tours and the occasional 5K.On Tuesday, observers were reminded that Mr. Zuckerberg, 32, is not just a normal guy who enjoys running and quiet dinners with friends. In a photo posted to his Facebook account, he celebrated the growing user base of Instagram, which is owned by Facebook. An eagle-eyed Twitter user named Chris Olson noticed that in the image’s background, his laptop camera and microphone jack appeared to be covered with tape. Other publications, including Gizmodo, used the tweet to raise the question: Was this paranoia, or just good practice?