This sound familiar? Facebook users are lashing out at the social networking behemoth for new features that, they grumble, cross the line and trample on their privacy. This time the evil enemy, for some privacy-challenged users, is none other than Facebook Places, the much hyped location-based service just launched to take on Google, Foursquare and others.

Here’s a story to get you up in the morning. Playboy has launched a “Miss Social” contest that gives Facebook fans the power to undress the next picture-perfect girl for an upcoming issue. Seeing naked girls? What’s not to “Like”? Right? Well, no so fast. Judging by the underwhelming early response, we’ve seen more panting over a Frappuccino.

Ad spending on social networks in the U.S. will grow to $1.7 billion this year and $2.9 billion in 2011, estimates eMarketer in a new report published today. That’s much improved on its previous estimates for 2010. Facebook is the major catalyst, but it’s but one driver. Here’s our take on which social media channels will be the primary drivers of social ad growth.

What new insights can we learn about the mercurial properties of influence from Hewlett-Packard, a company who’s chief influencer, Mark Hurd, is now out of a job for wining and dining a former B-movie actress on the company dime? Well, as Hurd now knows: don’t be seduced by fleeting fame. What really matters is who listens to you, respects your opinion and repeats what you have to say. That’s the true definition of influence. Yes, there’s a a Twitter angle here.

B2C social media initiatives get most of the attention, but that’s not to say there’s nothing innovative or interesting coming out of the B2B sector. In fact, business-to-business marketers are showing their savvy these days, even out-socializing most B2C players…

That’s the conclusion of the latest comScore study which finds that women spend far more time than men online connecting with their social network of friends and acquaintances. Perhaps that’s not surprising until you consider that women, on average, spend roughly 90 minutes more per month on social networks than men. That amounts to 5.5 hours/month for women on the likes of Facebook, Twitter and YouTube compared to about 4 hours for men.

As the tech press (and Diane Sawyer) prepare for the imminent, champagne-filled announcement of Facebook eclipsing the 500 million user barrier, we hate to be killjoys here at SMI but we feel it necessary to point out that the first 500 million, that was the easy part. For Facebook, the vast unconquered terrain lies in China, Japan, Korea and Russian-speaking countries where Facebook is an also-ran.

The mobile apps marketplace will top a staggering 25 billion downloads by 2015, according to new research by Juniper Research. To put that in further perspective: the estimate is that smart phone sales will reach 1 billion annually by the same period. That’s an impressive number of downloads per handset user.

Like the coffee fiends we are, we are anxiously pressing the refresh button on the Starbucks Facebook page as it nears an unprecedented milestone for a consumer brand: the first to 10 million fans.

Is Twitter adding a new pay-for-followers scheme to boost sagging brands and would-be celebs? What about a new real-time analytics tool to make sense of up-to-the-minute conversation streams?