Last June, the rapidly growing professional social networking site LinkedIn updated its privacy policy and made clear in that statement that social advertising was coming to LinkedIn, and that some personal information could be used in targeting these ads.

“The effectiveness of these recommendations is related to the people in a trusted network that it is shared with,” wrote LinkedIn’s Eric Heath in the message, “and one of the upcoming privacy policy changes lets us share your public actions, like recommendations, following companies, etc. on the site with your business network in a commercial context such as an ad.”

And so they did.

While many on the Internet were sent into a dizzying rage at the thought of LinkedIn pulling “a Facebook,” the site did, to their credit, create an opt-out setting on accounts if users absolutely do not want to be included in social advertising. As we all know, it’s much, much harder to opt-out on Facebook, which has drawn mass amounts of criticism for the way it seems to offer up personal user data to advertisers.

It is important to note, though, that not only are these changes a surpise (they were announced almost two months in advance), but that they also make clear in their initial press release that information will not be shared with third party marketers, but that their social advertising campaign will only use profile information that people in your network can already see.

“Most importantly,” said Heath, “we do not provide your name or image back to any advertiser when that ad is served.”

Some of the complaints are justified, however. One has to ask, if you’re giving an option in the first place, why not make in opt-in instead of opt-out?

The real question for marketers should be about the future of social advertising. If advanced notice and the opportunity to remove oneself from social advertising on a site with as clean of a record as LinkedIn can spur that much backlash and anger, is this really a field that has long-term viability? Maybe so, because regardless of the claims leveled against Facebook, users don’t seem to be too quick to leave.