Raid composition is an important aspect of WoW PvE. RaidComp (from now on denoted as RC) aims to be to raid compositions what talent calculators are to talent specs; allowing everyone to play around with and share different raid compositions online. RC also helps raid leaders by giving an overview of the different buff and debuff categories. It won't do all the thinking for you, raid optimization is complex, however it should be able to do most of the grunt work and highlight some of the categories and abilities you need to look closer at.