Updated

Here’s one you may not “like.”

Imagine having a friend on Facebook who matches up your privately shared data to a public voting record -- then flags you for more frequent campaign calls and contacts.

That’s exactly what the Democratic party is doing. The upcoming presidential campaigns are eager to get their hands on the treasure trove of voter data that 900 million users have voluntarily posted on Facebook. Enter Social Organizing, a new tool developed by Democratic activist group NGP VAN. Using it, your friends can log in to Facebook and tell the service about you. You can then be added to a caller database, pinged for ads and harassed during the entire election.

Many users think the information they post to Facebook cannot legally or ethically leave the site’s confines, noted Roger Kay, a technology analyst with Endpoint Technologies. They may be in for a surprise.

“[Facebook] was born on the idea of taking information about people and making it available to others … With political information, this sharing has become a notch more like selling out your friends,” Kay told FoxNews.com.

'With political information, sharing has become a notch more like selling out your friends.'

— Technology analyst Roger Kay

To use the tool, supporters log in at a campaign site. Social Organizing lets them connect to Facebook and locates friends. The supporter can then choose the relationship for those friends, such as co-worker or business partner.

Supporters earn badges and points as they flag these friends. The data is then matched to voter records.

For example, a supporter might have 500 friends, but the tool might know that 300 of those friends are already identified as donors or loyal to the campaign, based on voting record. The supporter can then focus attention on calling or e-mailing only the 200 friends who still need persuasion.

President Obama tapped this company, which describes itself as “the leading technology provider to Democratic and progressive campaigns and organizations” and only works with the Democratic Party, to gather voter data in 2008.

Stu Trevelyan, the CEO of NGP VAN, told FoxNews.com the company takes privacy concerns seriously.

"Our application is in full compliance with the Facebook policy, and we take their policy and privacy seriously." He explained that the app only uses certain pieces of Facebook data -- first name, last name, city and state -- to match people with voter records.

“The Facebook data just makes that process of identifying their friends on the voter file quicker, but this can also be accomplished without Facebook, with a name lookup" for example, he said.

Facebook spokesman Andrew Noyes declined to comment on the service. But the social network’s platform policy does explain what information can be shared by applications: “A user's friends' data can only be used in the context of the user's experience on your application."

Some experts argue the tool might stretch or even violate those policies.

Rob Enderle, a consumer analyst, says most people don’t even know that their Facebook can be mined in this way, for example. They might not be aware that, when you friend someone on Facebook, you are giving them permission to use a tool like Social Organizing and that you might start getting more campaign calls.

“Social sharing became one step more sinister when commercial activity was introduced, the product of having to satisfy shareholders with respect to revenue generation,” Kay told FoxNews.com.

“Facebook has a terrible record on privacy,” he said.

Trevelyan said the Social Organizing tool uses accepted practices: The voter record is public for each state, and it is a common practice for campaigns to mine this data. He says Facebook users can easily turn off private information such as data of birth or the city where you live.

The expert advice: First, head to Facebook’s privacy controls and make sure of how much you’re sharing, and with whom. Then choose your friends wisely. In a way, this “friend” is using the relationship for political gain, and yet you might have any knowledge that this social mining is happening.

“Anyone can take information and match it with public information and sell the result to someone else,” Enderle told FoxNews.com. “It's perfectly legal and not even immoral. But those are not the friends you want.”

Enderle says this could be a polarizing problem for Facebook. Some users might start turning off more private info, not realizing that they have been giving campaigns fodder for the election.

“Done well it could increase dramatically the effectiveness of campaigns. Done poorly this could cause people to abandon Facebook in massive numbers. I expect the result will likely be someplace in the middle.”