Before I tell you how to block Facebook's new autoplay video ads, a word about autoplay video ads: they're a bad idea. Not just bad like junk in your mailbox, but bad like someone planting a Vegas billboard outside your window that turns on any time you want to admire the scenery

When you scroll through your Facebook News Feed, whether on mobile or desktop, these video ads will now autoplay, the one concession being that they'll do so without sound — if you want to hear them, you have to click on them (that's how videos already work on Facebook when friends share videos with friends). The other concession is that the ads won't load on mobile devices unless they've first been synchronized via Wi-Fi, eliminating mobile data usage concerns. These are important gestures, but the visual distraction remains a visual distraction.

Unless you take other measures and block them, anyway. You can't scrub them out entirely using a multi-platform blocker like AdBlock (at least not without delving into custom CSS filters). But you can prevent the ads from automatically playing. Since they're Flash-based by default, you need a Flash blocker for your browser.

I use something called ClickToFlash in Safari: a free plugin that places a gray curtain over Flash content that remains unless you click to start it; the Chrome equivalent, which I also use, is FlashBlock, though AdBlock Plus (for Firefox, Chrome, Android, Opera and Internet Explorer, though not Safari yet — a version's apparently in development) supports tab-based Flash or Java blocking. I like ClickToFlash because it doesn't remove the content entirely, it just renders it inert, like firing a freeze ray at the neighbor's yippy toy poodle.

Facebook's new video ads support HTML5, so instead of a gray curtain, I see a fixed HTML5 snapshot of the ad, which I can either click to watch or right-click if I want to select and load the Flash version (if you just want to block everything, ClickToFlash lets you disable HTML5 fallback). Either way, the ad is frozen on appearance and control of playback is returned to me, where it belongs.

Facebook's notion of ad-blocking is to just "keep scrolling" past the ad. You can do that, sure, but it's a crude workaround and too big a compromise (if these plugins weren't available, I'd have to say goodbye to Facebook). Better to use one of these tools, then, if you want to maintain control of this aspect of your browsing experience.