So I'm watching MSNBC and during a commercial break they have an an ad that looks like a regular pharmaceutical commercial with the usual side effect blah, blah, blah. But then I it finally clicked that it wasn't medicine for humans it was for live stock to make them weight on average 28 pounds heavier and thus worth more money when they are sold. But that wasn't the weird part. The weird part was when I called my wife in to see the ad it had disappeared. I reversed the DVR back a few minutes and instead of the ad I had seen, instead was an ad for Dish Cinema. I had always realized that Dish inserted these ads (you could sometimes see the beginning of an ad cutoff by Dish ads), but how did they replace it after the fact. Something that I had actually watched was now gone and something I hadn't seen was in it's place. Has anyone else ever noticed this or have any idea how it was done?