The announcement and limited invitation to the new Google+ social network last week not only whipped up a frenzy of anticipation, but marked the first salvo in the new battle for the social media space.

Unlike the first rounds between Friendster, Myspace and others, this battle pits sophisticated players against each other in a mature market that investors better understand.

The main rivals, Google -- the world's largest search engine -- and Facebook -- the world's largest social network -- have deep pockets and large war-chests of talent, technology and clout.

At stake is the control of advertising revenue afforded by letting advertisers position messages directly in front of a targeted audience.

Spending on behaviorally targeted advertising, the kind that social networks are best suited to serve, is expected to swell  to over $5 billion in 2012 from the miniscule $300 million in 2006.

Beyond just revenue, this round of fighting can perhaps change the very nature of the Internet itself.

Facebook has the advantage of being a first mover, garnering already over 500M users worldwide. It's partnership with Microsoft, and the rollout of its Like button to 3rd part platforms is helping the company extend its reach beyond its own website.

But what Google lacks in social experience, it certainly makes up for in resources and general reach.

Google is the most trafficked site in the world.

With portal-like tendencies, like hosted email and news, and housing the most familiar, and arguably the most effective search engine in existence, Google acts as the front-door to the rest of the Internet.

In May of this year, more than 1 billion people visited Google properties, more than any other company at any point in time.

The implications of this are huge. Instead of creating a social network destination on the Internet, Google can, in-fact, turn the whole of the Internet social.

With recent overtures to partner with Facebook and Twitter rebuffed, Google may have to do just that to accomplish its end-goal.

But Facebook isn't standing still.

Facebook teamed up with Skype to offer video chat inside of its pages , adding deeper person-to-person connection as it ramps up its own game.

Facebook also has one very decisive advantage over Google -- its army of 3rd party developers creating apps, and making the world of Facebook richer day by day.

Zynga is a prime example. The creator of Farmville, Mafia Wars, and other Faecbook apps is set to go IPO for $1B, a move that almost qualifies the Facebook development model.

This isn't to be overlooked. Though virtually every other smartphone maker had a head start on Apple, the innovations in the iPhone brought users in, but the apps are making users stay.

Facebook founder Mark Zuckerberg hinted as much during the Skype announcement with a veiled shot at Google.

We want to leave all the applications to independent entrepreneurs and companies that are going to be best in class at building these things. That's a different strategy than other major Internet companies out there who try to do everything themselves, Zuckerberg said.

 Zuckerberg said that this represents only the first of many upgrades coming this year.

And with Google following suit, announcing upcoming changes to help even allow businesses thrive on Google+, rest assured these latest developments are only the beginning of escalating tension in the battle to control the social space.