Not that long ago, Google (Nasdaq:GOOG) was almost considered a has-been, stagnating in the “value trap” like other tech giants, such as Microsoft (Nasdaq:MSFT), Intel (Nasdaq:INTC) and Cisco (Nasdaq:CSCO).

It turns out Google’s death has been greatly exaggerated.  As seen with its latest quarterly report, the company still appears to be in the growth mode.

In fact, the company is attacking some of the pesky social operators — Facebook and Twitter, both of which have been fetching huge valuations.  And, as we’ve seen with the huge valuation of LinkedIn (NYSE:LNKD

), investors are extremely hungry to get shares in these social companies when they hit the public markets.

But why wait?  Google could be a nice proxy for the surging social-network growth.  It has recently launched its social network, called Google+, which is going like gangbusters, with 10 million registered users (the service is invite-only).  And they appear to be highly engaged, with over 1 billion items shared each day.

Of course, Google has a set of other franchise properties.  Besides its search cash cow, there is YouTube, Google Apps and Chrome.  However, perhaps the most promising business is its Android mobile phone software, which is seeing a whopping 550,000 activations a day.  It’s embedded in roughly 130 million devices and has seen more than 6 billion app installations.  Keep in mind that Apple (Nasdaq:AAPL) has more than 200 million devices on the market.

Let’s face it, mobile is a huge global opportunity, but it’s an extremely tough market.  Just look at the problems with Nokia (NYSE:NOK) and Research In Motion (Nasdaq:RIMM). But again, Google has been able to develop best-of-breed technology and find ways to get massive distribution. 

Yet despite all this, it looks like investors are still willing to value Facebook at $100 billion.  Assuming the company generates about $4 billion in revenue for 2011, its price-to-revenue multiple is 25. 

However, Google’s revenue multiple is only 5.  In other words, even with the recent spike in the stock price – it was up 12% in recent Friday trading — the company still looks like a compelling value.  More importantly, you are getting a much broader play on some of the fastest growing categories, like search, mobile, social, local and the cloud.

Tom Taulli’s latest book is “All About Short Selling” and he has an upcoming book called “All About Commodities.”  You can find him at Twitter account @ttaulli.  He does not own a position in any of the stocks named here.