Yes, Cramer can move some stocks. The smaller the capitalization of the stock, the more it would be affected. But you have no way of knowing when he will turn around and tell people to sell the same stock, or at least I don't. If you can do enough research and become good at predicting what he will recommend before he recommends it, and knowing which stocks would move on the recommendation, then in theory that might work but there have got to be easier ways to make money.
Back in the nasdaq madness 90's, some traders and I would make trades specifically based upon the stocks being mentioned on CNBC at the time. Lots of traders were doing this, but we were making money at it. The difference between us and the average losing traders was that we were predicting the news mention ahead of time. We knew that the nasdaq guy did a 10:15 report, so at 10:00 we would put our minds in the 'frame' of being the nasdaq market reporter guy. If I was a reporter and had to mention the biggest stock movers of the day, what would they be? I'd pick two or three, look at the chart, load up the buy orders, and watch CNBC intently. Typically, I was right on at least one stock to be mentioned, when I saw the reporter's lips forming the first syllable of the company name, I would hit 'buy', and I would own the stock before most of the word has left his mouth. Keep in mind that he talks quickly, too, so all of this is happening in fractions of a second. Then, all of the schmucks arrive. They did not do their homework, and had to spend three seconds loading up their buy orders. They bid up the stock like fools, and after only 10-20 seconds I sell my stock for points more that what I paid. When practically everyone was a day trader, this was how easy it was to make money. I doubt that trading off CNBC still works.