If a meta gem requirs 2 yellow gems does this just mean yellow sockets?
What I want to know is if I use a green or orange gem that matches a yellow or blue socket. Does this count as a yellow gem for the meta gem 2 yellow requirment?
From what I can understand, you must have 2 yellow gems equipped on your gear. It doesn't have to match the socket color, it just must be equipped. Thus, sometimes to gain the meta socket bonus, you have to break a bonus on another item.
This is based off my reading here (linked in the FAQ) and on WoWwiki.
And yes, your orange/green gems do count towards your yellow gem requirement.