The Guild Finder introduced in 4.1 is useful, however there is no order to the guilds that are presented.
This addon just adds a 'Sort' button to the in-game Guild Finder. Use /mygf to open the modified Guild Finder.
Guilds are sorted in 1 of three orders as you press the 'Sort' button
1) Level -> Guild Achievements -> Guild Name 2) Guild Name 3) Number of Members -> Level -> Guild Achievements -> Guild Name