Hinting, more accurately called instructing, is a method of specifying how digital fonts display at small sizes on low-resolution devices, usually for on-screen usage. This is accomplished by providing instructions in the font file that define which pixels are turned on when producing Bitmap images.
Generating TT OpenType Fonts
To autohint, or NOT to autohint…
Hints, good or bad? Is it really needed?
When is the better time to hint?
Legend of Raster: Glyph’s Quest for Pixel Solace
Who else wants to understand hinting?
John Hudson on autohinting TTF fonts from FontLab in Trying out Typekit
Microsoft: The raster tragedy at low resolution
or: why correct math looks wrong on screen and how to fix it
Microsoft: Hinting Tutorial
Typotheque: Font hinting by Peter Biľak