Other than the obvious suggestion to look in the right place on the forums, I'm not surprised that there isn't much random recruitment in-game. People use FCs to guild runs on end-game content. You don't want some random noob to gob up a static run.

The FC I'm in tests every single raiding member (exception for friends and family members). We'll take you on an end-game dungeon run (usually AK), and we'll just do stupid crap. The tank will pull too much (if testing a healer). The DPS will intentionally pull mobs (if testing a tank). The clear time will be graded (if testing a DPS). If you can't pass muster, you aren't invited. I doubt we are the only FC to do this.