“I PROPOSE, if and when found, to take him by his beastly neck, shake him till he froths, and pull him inside out and make him swallow himself.” It is not often that Silicon Valley’s denizens quote P.G. Wodehouse. But this is what Benedict Evans of Andreessen Horowitz, a venture-capital firm, expects the success of messaging services could do to both mobile and corporate software. The most striking example so far of this process came on March 25th when Facebook announced at a conference in San Francisco that it has started to turn its Messenger service into a “platform” that can carry, and be integrated with, all manner of apps created by other software firms.