By Richard Saintvilus

I've spent most of last year coming to the defense of Facebook (FB). Although I no longer own the stock, I'm nonetheless amazed by the volume of criticism the company still absorbs.

Granted, the botched IPO didn't win it many friends. But over the past six months, it is clear that Facebook has grown -- literally. In many respects, this is a new company. Following a solid fourth-quarter performance, it's time investors get a new perspective of what this social network giant can yet become.

Facebook is transitioning itself from what it was, which was a PC-dependent platform. This means the company is in the midst of a pretty significant transition. 

With its user base having exceeded the one billion mark, there's more urgency for Facebook to reconfigure its approach. This quarter proved that it understands this. It's time for investors to start doing the same. 

Mobile revenue was impressive, growing to 23% of Facebook gross revenue. Too, mobile monthly active users rose to 680 million, which means Facebook has begun to shed the most popular bear argument -- that it can't monetize mobile. This is the second consecutive quarter of mobile growth.

Advertising revenue was up 41%, which was the same as in the third quarter, and fell slightly short of estimates. Likewise, ad pricing shed roughly 4%. Normally this would have been a bigger disappointment. But then again Google (GOOG) didn't exactly outperform in that area either as it reported a 6% drop in CPC or cost per click -- the metric that tracks how much companies pay for ads. 

With a metric of $1.38, Facebook still lags behind Google's $9.16 in terms of average revenue per user. For that matter, Facebook is also behind Microsoft (MSFT). But all that means is the company has plenty of room to grow from the $1.59 billion in revenue it just reported.

Some of Facebook's ad weakness can be attributed to declining demand in emerging markets. It is something that bears watching, particularly since it is the company's first reported decline. However, there were also some red flags in profitability. For instance, not only did gross margins eased a bit on a year-over-year basis, GAAP operating income declined 5%.

Granted, Facebook is still a young company and profitability issues are not considered material at this point -- I get that. But good cost management goes a long way. It's not as if Facebook started with a clean slate here. The company is still trying to restore respect and trust. There's no better way to earn "Street cred" than with solid books.

All of that said, Facebook has made some meaningful improvements. However, the company is not out of the woods yet -- and it knows that. Facebook understands it needs additional streams of revenue. Sponsored stories is one example, as are new advertisement formats. There is Graph Search, which has garnered plenty of attention.

The company is looking to combine its marketing database with Internet search and Boom! -- cash starts spitting out. Well, not quite, or at least not yet. It is not yet certain how effective this new feature will be. In time, Facebook will be able to figure it out. It is encouraging, nonetheless, that the company is looking for ways to increase value. 

Investors shouldn't discount Facebook's ability to enter the corporate enterprise, a potential gold mine for the company and investors.

For example, if Facebook is able to adopt the enterprise benefits of Microsoft's Yammer by allowing employees to chat, share information and contact each other via private directories, Facebook's new corporate presence would then immediately rival that of LinkedIn (LNKD).

What's more, with the adoption of Facebook into Apple's (AAPL) mobile IOS, as well as other investments made by Microsoft, there are powerful allies in Facebook's corner. With one billion users now on hand, Facebook will have plenty of ways to make money. In the meantime, its growth trajectory puts its fair value at $40. (Microsoft owns and publishes Top Stocks, an MSN Money site.)

At the time of publication the author had a position in AAPL.

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