Font Management in Linux
Fonts in Linux are crazy. Most Linux distributions ship with a big blob of serif, sans serif, and monospaced fonts, and there's barely a pixel's worth of difference between them.
Fonts on computers are crazy. Sometimes I pine for the olden days of swapping out the type balls on IBM Selectric typewriters to get different fonts. You always knew what you were getting with those.
Many fonts are copyrighted, so you cannot legally copy them and give them away to all of your friends. Some applications come with their own sets of fonts and rendering libraries. The GIMP does this because it thinks it can handle fonts more competently than your X server; it uses FreeType and Pango. OpenOffice.org also comes with its own set of fonts, for what reasons I know not.
The good news is your system is probably already set up to share all these fonts system-wide, and FreeType and Fontconfig are becoming standard.