Any of these. That article also explains what, why, and when for different types (whey, casein, hydrolyzed casein, etc.)
Not totally accurate. Plenty of cheap-o brands, and more than a few more well-known brands, have been caught amino spiking - basically lying on the label and claiming X amount of "protein" while counting anything from gelatin to individual aminos as part of that total. This article talks about it and a quick Google will bring up a list of companies that've been busted and/or have ongoing lawsuits about it.