Chapter Approved
Chapter Approved is a "stamp of approval" that Games Workshop used to put on rules published in White Dwarf that were meant to be official. Back in Third Edition, every issue of WD had a column where Andy Chambers (and other Warhammer 40,000 writers) would write rules clarifications, errata, new army lists, and experimental rules (some of which were used in later editions); these columns were then combined into annual Codex-type volumes in 2002, 2003, and 2004. These articles were on average fucking awesome and generally upped the greatness of the Dwarf immensely. Examples of awesomeness include trial rules for using Space Marine Chapters of the Cursed Founding; information on the Imperial Guard regiments of Armageddon; and rules to allow the use of Inquisitorial henchmen. It showed as well that at the time Games Workshop actually acted like a game company and gave the public something they wanted; a bit of extra fluff and some different rules to add a bit of spice to their gaming.
Unfortunately, with Chambers' departure from GW (and Games Workshop's general descent into corporate evil), the column fell by the wayside, and the "Chapter Approved" stamp is only seldom seen nowadays. At the time this also marked the removal of story and fluff elements slowly from the Dwarf in favor of more painting guides and adverts, until now any fluff is a mere whisper in the wind crowded under the latest Space Marines that you just have to buy!