You're LinkedIn's latest advertising star - didn't you know?

LinkedIn made a bad social advertising call, but we should know better than to trust social media...

...face of their brand and you would have no control over where that face would appear unless you'd unchecked that all-important box.

Now faced with a backlash from users, the company has changed how its social ads will look, taking out the names and photos of LinkedIn users and replacing them with the vaguer, '11 people in your network follow company X on LinkedIn'.

LinkedIn's director of product management Ryan Roslansky said in a blog post: "We hear you loud and clear."

"What we've learned now, is that, even though our members are happy to have their actions, such as recommendations, be viewable by their network as a public action, some of those same members may not be comfortable with the use of their names and photos associated with those actions used in ads served to their network."

So far, so good, but LinkedIn isn't the first social network to trade off privacy policies that opt users in automatically. Facebook does exactly the same thing. If you've Liked a product or service, that product or service can use your image in its advertising. silicon.com features users who have Liked the site on its homepage, for example.

There's a simple reason for this practice: this sort of social advertising is powerful. What better testimonial to a brand than evidence of the approval of real-life users? And what better way of getting as many people involved in that endorsement as possible than opting them in in bulk, rather than going through the tricky process of having to gain their express approval to be used in such a way?

Now at least LinkedIn's social ads, even in their watered-down form, can be circumvented. By editing your 'manage social advertising' settings, you can opt yourself out of unknowingly appearing as a company's cheerleader.

However, you don't have quite the same scope with Facebook. Its terms and conditions state: "Facebook is designed to make it easy for you to find and connect with others. For this reason, your name and profile picture do not have privacy settings. If you are uncomfortable with sharing your profile picture, you should delete it - or not add one."

You may hide other elements of your social networking activities, but not those that most define a person and that most individuals would guard most closely - your face and your name - and must yield them to marketers.

Of course, if we were concerned enough about these issues, we would simply leave social networks in protest. We could opt out entirely.

And yet we don't. We are too attached to the pictures of our friends on holiday or the prospect of making a connection that will lead to a new job.

It is not our passive backing of the wares of advertisers on the likes of Facebook and LinkedIn that should worry us most. It is the unthinking testimonial we offer to the strength of social networks. By staying with them regardless, we signal our silent approval. And what greater testament to their services do they need?