Oct 17, 2012 · 4 minutes

The lifespan of tech stars seems to be growing shorter and shorter. It used to be that companies like Intel and Microsoft would rule industries for a decade or more before new technologies would turn them into also-rans. But it was less than a decade after Google was founded and only three years after it went public that some people were predicting Facebook would kick its search-engine butt.

For a while, that prediction seemed to be coming true. Facebook's monthly-user metric ticked steadily toward 1 billion and the social-network upstart was stealing ad revenue from Google's searches. AdWords was dying a slow death, thanks to the SEO plague and the endless tweaks that Google made to its results page. But above all, social media meant people were discovering content through their friends more, and searching for it less.

As a result, few people were surprised when Google's stock flatlined for a few years, vacillating between $450 a share and $650 a share from the summer of 2009 until the summer of 2012. But beginning in June, something unexpected happened: Google's stock began to rise, moving from $557 to $774 earlier this month. It blew right past the $747 record it has set in 2007, a level some thought Google might never see again.

And it all started a month after Facebook's IPO fizzled. Facebook is currently trading 49% down from its $38 offering price. Google is trading 18% higher since the day of Facebook's IPO. In fact, since Facebook went public, its stock has lost $51 billion in market value. Google's stock, meanwhile, has increased by more than $120 billion.

What those numbers tell us is surprising. The amount that Google's stock has gained in the five months since Facebook's IPO is more than Facebook was worth when it went public. Or, put another way, Google is now worth four-and-a-half Facebooks. Whereas several months ago, Google was worth only two Facebooks.

You have to wonder how much of Google's gain was caused by investors cashing out of Facebook and putting the money into Google. Last year, before Facebook filed for its IPO and revealed its financials weren't as strong as many were expecting, it looked ready to supplant Google as the premiere Internet investment – the best proxy for the steady, healthy growth in online advertising. Ever since Facebook started trading, however, the crown has returned to the Googleplex.

The rise and fall in share prices isn't just a concern for Wall Street. Many employees at Google and Facebook also hold shares or options, just as many startups looking to be acquired prefer their buyer to have a stock likely to appreciate in the future. Beyond that, investor sentiment can reflect a broader public perception of a company: In the case of Google, its brand is getting stronger, while Facebook's is getting weaker.

Not all of Google's gain can be tied to investors disappointed with Facebook. The threat that Facebook posed to Google prompted Larry Page to take bold steps to remake the company. He reorganized its structure to sharpen its focus. He cut many features and built the rest around Google+. He waded into controversies like Search Plus Your World (inviting employees who didn't like that change to work somewhere else). He grew YouTube into a vast global TV network supported by video and banner ads. And he paid $12.5 billion for Motorola Mobility because... well, it's still not clear why Google did that.

More recently, Mark Zuckerberg has been engaged in his own efforts to renew Facebook's revenue growth, introducing the Facebook Exchange ad network and dropping hints about how Facebook will push further into search – both moves that resemble Google's traditional model. Social networks may be signing up more users, but it's still easier to get someone to click on a search ad than it is to get them to respond to an ad next to, or even inside, a news feed.

Google and Facebook's offerings are starting to resemble each other because as the web evolves, its features tend to merge. Search and social networking used to be distinct business models, but the lines separating them are blurring. As that happens, Google looks – at least for now – to be better positioned. eMarketer expects Google to surpass Facebook in display-ad revenue this year. Analysts estimate that nearly a quarter of Google's revenue now comes from mobile and display ads, freeing it from its longtime dependence on web-based search results. Android is giving Google a foothold in mobile that Facebook can still only dream about.

So Google's new ascendancy in the wake of Facebook IPO is about more than a botched stock offering, or even the challenges facing Facebook in the next year or so. It's also about Google's recent push to position itself in every segment of the consumer internet – mobile, video content, search, cloud apps – and to keep selling ads in all of them.

Well, okay. There's one area of the consumer Internet that Google still isn't positioned very well in: social media. But instead of betting on social versus search, Google seemed to understand a while ago that the two were moving toward each other, even within the same web site. That's a realization that Zuckerberg seems to have made only recently. If so, then maybe Google is thinking further ahead than Facebook about how the web is evolving next.