NEW YORK ( TheStreet) -- It's hard to imagine that a little more than a year ago the Street was debating whether Yahoo! ( YHOO), which was in the middle of yet another leadership change, had enough left in the tank to survive.Then the company's board, which had not had a strong reputation for making sound decisions, threw Wall Street a curve by hiring Marissa Mayer, a smart but unproven tech guru. I don't believe we can continue to refer to Mayer as unproven. Last week, comScore, a Web traffic analytics company, issued its monthly report on the most visited Web site in the U.S. and -- surprise! -- Yahoo! eclipsed Google ( GOOG) as the most popular Web destination for the month of July. The report revealed that Yahoo! attracted roughly 197 million unique visitors, while Google came in second with 192 million. This is the first time in more than two years that Yahoo! has earned the top spot. Aside from the affirmation that Mayer's new leadership initiatives are working, what does this new status mean for Yahoo!, if anything? I don't mean to sound unimpressed. I want to make it known that I am a Marissa Mayer supporter. I believe in her methods. I also believe that the media have (among other things) exaggerated her hard position on workplace issues, especially those that are typically sensitive to women. Nevertheless, given that AOL ( AOL), which has had one foot in the grave since the advent of broadband, came in fifth on comScore's report, it's hard to get excited about Yahoo!'s rise to No. 1. MSFT), not known for having built a successful online presence. In fact, I will argue that Microsoft's failure to capitalize in the new social media era where Twitter and Facebook ( FB) have become so dominant will go down as one of Steve Ballmer's all-time blunders.