Friday's guide discusses the differences between Limit Hold'em and No Limit Hold'em.
"One of the fundamental choices when deciding to play poker is what game you will play. Most players choose to specialize in either Limit or No Limit/Pot Limit variations of poker. Each variant has different betting dynamics that give each game a unique feel."
The article can be found in the beginner guides sub section of poker guides area of the poker section in the sub tabs.