How to use Quarks?

[Patrick Braga <theunixgeek lists gmail com>]

I've just begun learning GLib, and I came across Quarks. The documentation 
describes them as "association between strings and integer identifiers. 
Given either the stringo or the GQuark identifier it is possible to 
retrieve the other."

This seems really useful and all, but I have no idea when this could be 
applied. I don't necessarily want code examples, just something like "if 
you want to do this then you could use quarks to..."

Thanks!

Patrick Braga
http://theunixgeek.blogspot.com