It showed what items were on the rise, which ones were stagnant, and which ones were going down. I don't know how accurate it is since I am not familiar with my realms AH yet. I put some things on the AH with the Zygor suggested price and sold about 5k worth of stuff (I had a ton of MoP gems/herbs sitting around). I did use TSM suggestions as well and for the most part they seemed pretty close. But I did do an AH scan with Zygor before posting.
Well. LFG is designed to replace blizzard's premade groups entirely just like custom raid frame addons (like grid, grid2, healbot) did towards blizzard's compact raid addon. We can actually do little customization towards Blizzard's UI unless we write our own "UI". Instead, just use LFG to create/search groups instead of blizzard's UI since it sucks.
Often the name modification (or "mod" for short) is used interchangeably with AddOn. More specifically, a mod is a third-party AddOn that alters or enhances some aspect of the game's interface. Mods can perform a wide variety of tasks, including adding new buttons to the screen, altering the built-in player and party frames. In extreme cases, mods completely supplant the standard game's interface, usually offering more advanced functionality.