Another good reason to be annoyed by autoplaying videos online: it eats up dataplan allowances, making for some rude surprises. I'm always nervous about data allowances, and sites should be cautious about what they shove at you; turning off the autoplay feature isn't hard (and it's explained in the second article linked above), but I sure wish it was the default setting, or at least caught and handled by a browser extension. (Perhaps this is a job for Social Fixer's next iteration.) Is Facebook the worst offender on this front?