The names of Rare quality items will appear in blue.
Equippable items of Rare quality almost always have one or more attribute bonuses and some have procs.
As an example, the blue weapons have at least 3 "major" stat boosts, and eventfully a proc. This also occurs with most armor (head, neck, shoulders, chest, back, waist, legs, boots). Backs, bracers and some trinkets/rings only have one or two stat boost, a proc, and/or an "On equip".
Most equippable items at Rare quality and above can be disenchanted by characters with the Enchantingprofession.