I still think it's something very simple, like +1 damage or armor. It can affect any gear that you are wearing at the time, just like heirlooming. It's also supposed to be rare (I and many others still haven't seen this message), so I don't expect the bonuses to be too trivial.
The wording of the phrase is a lot like RPG code for "you've leveled up." It could be that all/one of the pieces of gear you are wearing has "leveled up" and increased many of its stats. We just can't see the increases. At least not yet. Honestly, how noticeable is a single +1 damage, speed, or armor in practice?
Also, there has to be something better than "chadztext."