Bosskillers does one thing and does it well: raid boss strategy guides. They vet for quality with some pretty straightforward guidelines for their guides, like "Detailed positioning instructions. Diagrams are required unless the positioning is extremely simple" and "Any special gear requirements (eg. resistance levels for different classes) should be included." Bosskillers guides are required to be in well-written, easily understandable English, with the goal that everyone in the raid should know where they must be and what they must be doing at any given moment during a boss fight.