More people are still Yahooing, with the company announcing in its earnings release yesterday that it had the most unique visitors to its U.S. sites in Dec. 2003 (over 111 million).

While keeping its focus on "great products equal a great business," Yahoo! (NASDAQ:YHOO) has been able to effectively monetize its enormous base of visitors. In the fourth quarter, Yahoo! generated net profits of $75 million or 11 cents per diluted share, up from $46.2 million for the same period a year ago. Revenues soared to $663.9 million last quarter, compared to $285.8 million in the year-ago period.

Leading up to the Yahoo! results, there was quite a bit of giddiness about how good the numbers and guidance would be. So, investor disappointment was inevitable as the stock price declined -- which was also the case with the reports from Apple (NASDAQ:AAPL) and Intel (NASDAQ:INTC).

Yahoo! has made strides with its subscription businesses, such as with job listings, dating, email, and DSL services. There are close to 5 million paid subscribers, with expectations for 7 million to 7.5 million by the end of 2004. It has also entered a joint venture to create an auction site in China with Sina (NASDAQ:SINA).

Yet, Yahoo! is still a marketing company, which means it is absolutely critical that it dominate search. This means a full-scale attack on Google. After all, estimates are that privately held Google could raise $4 billion in an IPO (Yahoo! has $2.5 billion in the bank).

So far, Yahoo! has demonstrated strong execution on search. The integration of Oveture seems to be ahead of plans and its relationship with Microsoft (NASDAQ:MSFT) has extended to Europe and Korea.

It is no secret that Microsoft is developing its own algorithmic search platform, which could jeopardize the Overture relationship (but this could still be a year away). Amazon.com (NASDAQ:AMZN) and others also are trying to come up with the technology to create a "Google killer."

Yahoo!, however, appears to be the most formidable competitor. The first strike appears to be the first quarter, as Yahoo indicated it will introduce a wide array of search features among its properties -- and, yes, dump Google as a partner.

Do you Yahoo! or Google it? Your fellow Fools want to know on the Yahoo! discussion board.

Tom Taulli is the author of six books on investing, such as Investing in IPOs (Bloomberg Press), as well as a professor of finance at the USC School of Business. You can reach him attom@taulli.com.