I'll add...
Our item levels have far outpaced our actual character level. The difference in power (of whatever sort, based on stats) between a level 50 in level 50 gear and a level 50 in level 100 gear is drastic. Folks talking about item level sync in level 50 dungeons or Frontlines (already in the game) mean reducing this difference by capping the item level (like Frontlines caps at 80). You'll see the yellow marks on your gear when this happens, like in lower level dungeons. Item level sync weakens your gears' stats, not yours (except when in lowbie dungeons of course, when both are affected.)