Achievements/Feats of Strength

From Blizzard's official Achievements Preview:

"Feats of Strength represent the past glories of Azeroth, and as such, players will find them very difficult -- if not impossible -- to earn. They’re worth no points, and unlike normal achievements, unearned Feats are not displayed in the achievements interface. Feats include old-world player-vs.-player ranks, obtaining rare mounts, special titles, and more. Feats of Strength will be awarded retroactively (that is, they’ll be immediately granted to your character if you qualify) since many of them will be impossible to earn in Wrath of the Lich King."