Mad Money Mailbag: An Alternative Energy ETF

Editor's Note: The following are questions received from viewers of "Mad Money," seen every day at 6 p.m. EDT on CNBC.

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Jim, is there an ETF that tracks alternative energy stocks?

-- Gus from Long Island, N.Y.

James J. Cramer: One popular ETF that tracks alternative energy plays is the Powershares Wilderhill Clean Energy Portfolio(PBW). It holds 36 stocks in the alternative energy business, including Capstone Turbine(CPST), Plug Power(PLUG) and UltraLife Batteries(ULBI), and the diversity may help protect investors from some of the wild swings you see in these types of stocks.

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Jim, what do you think of eBay's(EBAY) buy of Skype?

-- Mary from Boston

James J. Cramer: I am not a fan of eBay after this deal. I believe $3 billion is too much to pay for something eBay will be giving away for free, and it looks like a sign that the auction business could be slowing down. The bigger takeaway is that Skype could do some real damage to the big telcos like Verizon(VZ), now that Skype has a powerful backer in eBay.