eBay ( EBAY) CEO Meg Whitman likes to mention "the Power of Three" when talking about her company. It's a reference to the combined might of eBay's auction business, the PayPal payment service and Skype's popular Internet telephony service. It must be frustrating, then, to have investors hone in on the weakness of one thing or another -- whether it be eBay's decreasing core auction business, recent listing lags in Germany or setbacks in China -- instead of the promise of the overall vision. Despite a holiday season that saw a record number of online shoppers and a continued strong showing for PayPal, which continues to dominate its market and contribute ever more to eBay's bottom line -- even as Google ( GOOG) redoubles its efforts to promote its rival Checkout service -- investors could not seem to stay behind the stock in its fourth quarter. eBay heads into that quarter's earnings Wednesday down roughly 11% to $28.62 since announcing its third-quarter results. That decrease is in contrast to the gains posted over the same period by other big Internet names such as Yahoo! ( YHOO), Google and Amazon ( AMZN). Trading at about 24 times forward earnings, eBay seems cheap when compared with others in the Internet sector, especially considering that the San Jose, Calif.-based company owns three of the top online consumer brands and that the migration of customers to the Web continues unabated.