Yeah sure you can over smoke meat. Like Bruno said, it's like any other flavoring. Just like you can use way too much garlic, you can easily overdo the smoke.
As for the black skin, I'm gonna guess you were running at a lower temp for at least few hours? This combined with a lot of smoke (adding chips to the pan throughout the smoke, using more than a few chunks of wood etc...) can really overdo it. The blackness kinda turns me off, and renders the skin pretty much inedible, so I try to avoid it. I run much hotter temps (325˚+) for poultry and use a stronger flavored wood like hickory or mesquite for a shorter time. I also, when time permits, give my birds at least a few hours uncovered in the fridge to dry the skin. The result, in most cases, is a nicely browned, perfectly edible skin and meat that's well smoked.
As for white, billowing smoke, I'll agree that can cause black skin and an acrid taste. However, to point out the exception to every rule, I once had gone a little too lightly on the smoke. The bird was approaching it's final temp and still looking quite pale. In a panic, I brushed the skin with butter and tossed 3 or 4 large chunks of wood into my coal basket. White smoke immediately began to billow in Biblical proportions, filling the entire block. Within 20-30 minutes the target temp was reached, and when I opened the smoker I discovered the most beautiful chestnut brown skin I've ever seen!! It hadn't had enough time to ruin the flavor with creosote, but the smoke flavor was definitely really strong and the color was perfect.
My point is, like anything else, a little or a lot is your preference. Sometimes you also have to break the "rules" to get the result you want.