Xah Lee, 2010-08-15, 2010-12-09
If many characters are displayed as squares or question marks, that's probably because:
As of 2010-12, latest versions of Firefox, Google Chrome, Opera, will show ~100% of the chars. Safari on the Mac will also show almost all chars. Internet Explorer 8 and Safari on Windows Vista are worst.
To get proper fonts, see: Best Fonts for Unicode.