I find it extremely distracting. A little hard to describe, but it is sort of like trying to remember one number while someone is babbling other numbers, or trying to keep a train of thought while listening to multiple other conversations.

There's also the visual noise - I hate it for the same reason I hate tool tips and similar. Popping up flyovers on top of whatever I'm trying to focus on is utterly infuriating and I've never understood why people think that's good UI. It is like shoving your hand in my face if I look at you.