The main difference among other space characters is their width. U+2000..U+2006 are
standard quad widths used in typography. U+2007 figure space has a fixed width, known
as tabular width, which is the same width as digits used in tables. U+2008 punctuation
space is a space defined to be the same width as a period. U+2009 thin space and U+200A
hair space are successively smaller-width spaces used for narrow word gaps and for justification
of type. The fixed-width space characters (U+2000..U+200A) are derived from
conventional (hot lead) typography. Algorithmic kerning and justification in computerized
typography do not use these characters. However, where they are used (for example, in
typesetting mathematical formulae), their width is generally font-specified, and they typi-