Years ago, London ruled one-fourth of the world's population. Now? Training its civil servants how to tweet “issues of relevance or upcoming events.” The UK's Cabinet Office original story titlehas published a 20-page “how-to” of sorts, the goal of which is to encourage civil servants to learn and use the micro-blogging service that, one day, will bring clean drinking water to the more than 1 billion people in the world who lack it.