1827: The “No child left unvaccinated” act becomes the law for Boston schools.

Smallpox was a deadly, disgusting disease, with the nasty habit of killing one-third of those who contracted the disease, and maiming those who were fortunate enough to survive it.

Boston’s declaration came just three decades after Edward Jenner discovered in 1796 that blister pus from those infected with the less-deadly cowpox could be used to immunize humans from smallpox.

Following Massachusetts’ lead, cities and states across the United States passed laws throughout the 19th century requiring citizens and...

Everybody knows that it’s inappropriate to tweet from the toilet. Of course, that’s not stopping social media entrepreneurs from butting into every aspect of our lives. And why not? There’s megabucks to be made. If Facebook goes public next year as expected, estimates peg its valuation at up to $100 billion. Even humble microblogging site Tumblr is supposedly worth about $800 million—almost as much as The New York Times. So whether you’re sitting on the throne or talking to a soda machine, there will soon be a new social feature urging you to share. You like to share, right? Right?!?!