Several unicode characters are not displaying on many big sites (like this: ⁠)

http://www.fontspace.com/james-kass/code2000 (3.73MB)

Code2000 font — Created in 1998 by James Kass .. Code2000 is a work-in-process. It currently (Version 1.171) has over 60000 glyphs.

Although it is more-or-less readable at 12 - 18 point, it is much clearer at about 24 point. Some of the dingbats should be at least 36 point. With font- smoothing it looks good at normal sizes.

There is a blog that mentions it
http://gschoppe.com/blog/fixing-unicode-support-in-google-chrome/
But the blog gets lots of things wrong in its description. (See comments on your question, for some examples. But his description doesn't matter)

You found the instructions mentioned on the blog worked, which was to extract the zip into the fonts folder in control panel and restart chrome.

http://gschoppe.com/projects/fbformat/includes/unicodefont.zip

Boxes or squares showing up in place of actual glyphs is a side-effect of the font you are using not having that Unicode character incorporated. Try looking for a font with a more complete Unicode implementation.