FYI: The typographic term for "intercharacter spacing" is "mortising" or, more commonly, "kerning."
Both terms refer to adjusting the space between font characters to improve visual appearance and enhance readability.
It can be done in two different ways. Kerning
is the practice of adjusting the spacing between individual character pairs. Tracking
adjusts the spacing proportionally between all characters in a selected block of text.
There's a huge amount of information, debate, and discussion about this topic up on the web. A quick Google/Bing search will bring up hundreds of articles.
For hardcopy print, the general rule of thumb is: TNT (tight but not touching). For onscreen and web typography, the jury is still out although it's generally conceded that a looser track is easier and less fatiguing to read than a 'tight' one for most users.