1. Here it's being used as a noun. "Critics of <something>" = "people who are critical of, or who criticize, <something>". Technically, "criticism" could be either positive or negative. The same is true of the word "judge". But when people say "critic/al/ize", they're nearly always implying negative criticism. Also, when folks say "don't judge me", they mean "don't judge me negatively" (which is an unreasonable request). 2. A board is, literally, a large plane of some material, often wood. A table-top is a board. And a committee (or group of people) sits around a table. Hence, a committee, or set of people who work together to make decisions, is known figuratively as a "board" (whether or not they actually sit around a table). An advisory board is a set of smart people who get together and discuss business management or policy and give advice to either an individual or a company.