I think Cramer is very knowledgeable about a wide range of stocks. His knowledge is thin on some stocks, but he seems to be able to express an opinion on most, as demonstrated in his "Lightning Round".
As I stated before, I think his show is very entertaining, which of course is his purpose, and he can provide a lot of ideas for the individual investor. No individual can afford to follow Cramer religiously. If you keep cashing out with a couple of $ profit (or loss) comission and tax will eat you alive.
A notable recent examble, as well as SLE, is how his opinion changed on the oil stocks. He loved them at the peak in oil prices, but grew more cautious as the price of oil fell. This week he issued a sell on the biggest oil, XOM, and recommended buys only on companies small enough to be bought out. Thanks a lot Jim. Following his advice would have cost a ton.
His opinions are no reason for an investor to not do his or her own research. He seems to have possibly gathered a big enough following to move some more thinly traded stocks in the short run.
But as Cranmer or possibly some other market pundit has stated, virtually every share traded is sold by someone who thinks a stock will go down, and bought by someone who thinks it will go up.
Bottom line, and my last comment on Cramer on this board, a poster who quotes Cramer to back up a buy or sell opinion is contributing little or nothing to the discussion.