It’s not exactly a “hack” to suggest hitting Monster.com, or your LinkedIn network, to check out job offerings and work your connections. Each site amongst our five best online job search sites, however, puts you in a different pool of possibilities, and each has its own quirks and tools. They’re somewhat perfunctory and broad, but wouldn’t you feel bad knowing you missed a great opportunity simply because it wasn’t in your super-specific Craigslist search?