I also agree that when bulking, you should try to eat clean for almost all meals, just like DaFreak mentioned in his photo thread. If people bulk with reckless abandon and consume fast food and a lot of other crap, they will get fat!
I have learned this the hard way in the past. Now, when "bulking" I slowly add more food/calories to the mix, while still eating clean. I manipulate the type of food I eat, rather than going nuts and eating pizza, fast food and too many carbs and processed foods.
Basically, my "bulking" diet consists of more meals per day, more carbs (mainly from whole-wheat bread and pasta and brown rice, more potatoes) and more protein too. Since I'm trying to get leaner, I'm no longer eating the bread, pasta, rice and am eating much less of the potatoes. And instead of 7-8 meals a day, I'm eating 5-6.