Cannot play videos on Yahoo! News?

Symptom: This often happens with users of Firefox and other Gecko-based browsers, when:
• they can't show most news videos on the Yahoo! News website and some other Yahoo! properties;
• the commenting system is not functional (can't properly view and post comments).

Privacy-conscious users, and/or those who wish for their browsers to consume less resources, use a script blocking add-on, such as NoScript. I often have NoScript configured to allow/disallow full domains (like d.yimg.com) and not just second-level domains (just yimg.com).

As it often happens, allowing only full subdomains instead of just second-level domains brings with itself more issues.

By default, NoScript includes a whitelist of second-level domains without which major services' functionality would be wholly disabled. The whitelist also contains yahoo.com, yimg.com, and yahoopis.com). The instructions herein are for users who have chosen to impose a more fine-grained control over the websites they visit.

Right, well, I finally played around with NoScript and found a solution:

NoScript:

In addition to news.yahoo.com and screen.yahoo.com and maybe others, allow the following domains essential for video playback:
• l.yimg.com
• d.yimg.com
• connect.facebook.net (If you're privacy-conscious, then allow temporarily).
  
  
11.07.2012. Update: I later discovered that non-video news items also featured videos, so here's an addition of domains that must be allowed:
• video.query.yahoo.com
• yep.video.yahoo.com
• yui.yahooapis.com (important on other Yahoo properties, even if not using video)
• webplayer.yahooapis.com

Flashblock:
• Allow d.yimg.com

^ Including only that domain in the Flashblock whitelist will have the video area rendered with the Flashblock placeholder. Clicking on it will start playback (note that ads are also played).

• Allow l.yimg.com

^ In regular news items that included video, disallowing l.yimg.com wouldn't even load the Flashblock video placeholder.

If you want video to load automatically, allow the above domains, and news.yahoo.com and screen.yahoo.com (and/or other Yahoo! properties as necessary from the Flashblock toolbar button).

Conclusion

Even if l.yimg.com and d.yimg.com are enabled in NoScript, the crucial part for some erroneous coding reason is connect.facebook.net; If that is not allowed, most video code and commenting functionality won't load. Note that connect.facebook.net is the primary culprit. This has been discussed before at forums.informaction.com (a NoScript and web security forum).