In spite of its slide, Internet search engine Google Inc. (NASDAQ/GOOG) is valued at a whopping $112 billion, not too bad for a company that made its IPO debut on August 19, 2004.

 Google's success has been largely driven by the turnaround in the online advertising market that has generated tons of cash for this company that derives the majority of revenues from its advertising programs. Google is a play on online advertising.

 The trend for online advertising is clearly positive. According to a study by PricewaterhouseCoopers LLP, the U.S. online advertising industry saw revenues in the January to March quarter rise another 38% year-over-year to a record $3.9 billion. The sequential growth was 6% versus the Q4.

 Google is currently the top stock in its class. Its annual growth is superlative. Its estimated five-year annual earnings growth is 30.5% versus 26.50% for rival Yahoo Inc. (NASDAQ/YHOO). Google's current valuation remains somewhat attractive versus its peer group.

 Google is trading at 29.60x its estimated FY07 EPS of $12.56 versus a more expensive 44.49x for Yahoo. Google's PEG discounting out the free cash of $27.81 per share is an attractive 1.19, Compare this to Yahoo, whose PEG is well over 2.

 At this time, Google is probably the superior Internet play, but the stock recently shown some cracks in its growth. Momentum stocks like Google do well as long as the company can deliver the extraordinary growth that investors have been accustomed to. Any deviation from this, as in the 2005Q4, could drive sellers to the exits as was the case with Google after trading as high as $471.11 on January 11.

 But make no doubt about it, Google is a premier Internet play. But also watch out as Yahoo and eBay Inc. (NASDAQ EBAY) will work together on Internet projects that ultimately may take aim at Google's perch on the top of the Internet world.