To find out accurately what information about my “browsing habits” was being used — and how it had been collected — we had to go behind a scenes, into a difficult universe of online information tracking and targeting.

I was usually vaguely wakeful of ShareThis, and hadn’t satisfied it had anything to do with advertising. The association is substantially many widely famous for a tiny pity buttons on many sites that make it easy to post stories onto Twitter and Facebook.

You can find ShareThis widgets opposite a web, from a Los Angeles Times, The Boston Globe, New York magazine, and The Huffington Post, to a Food Network, and Us Weekly.

Barry Grant, an executive in assign of remoteness during ShareThis, told me that a association indeed gives a widgets divided for free, and also includes statistics that tell publishers what’s being shared, and where.

What it gets in sell is information about what sold surfers are reading and pity opposite a Internet — a profitable trove of information that it uses to aim online ads.

The association works with scarcely 1.4 million opposite websites, all of that have concluded to let ShareThis collect information about their visitors.

The association uses a tiny calm record called a cookie to lane a function of any caller who has used a ShareThis widget. The cookie allows ShareThis to continue to collect information about what someone is observation as he or she moves from site to site. (ShareThis allows users who don’t wish to be tracked to opt-out.)

When an advertiser comes and tells ShareThis that they wish to uncover an ad to people who are meddlesome in Republican primary elections, ShareThis can brand a organisation of people who have recently review articles or watched videos about a primaries, and uncover them ads.

This means that ShareThis has a ability to assistance a Romney debate brand groups of electorate meddlesome in sold issues — and given Romney’s debate website uses ShareThis buttons, a association is also collecting information about visitors to a campaign’s possess site.

Even before a debate central reliable that they did aim ads during users who visited a debate site, ShareThis’s Grant pronounced that he was “100 percent certain” that my visiting a site “was a vital factor.”

While a Romney debate central reliable that a debate targets ads during users who visited a debate site, a central — who declined to be named — wouldn’t go into fact how a targeting was done.

Grant pronounced ShareThis could have also worked with a Romney debate to aim users meddlesome in a accumulation of topics, from extended categories, like people who revisit pages about “Republicans,” to some-more slight ones, like people meddlesome in “No some-more taxes.”

He forked out that some advertisers also select to aim people who are meddlesome in their competitors. “Let’s contend Nissan wanted to go after people pity calm on Hondas. We could find people who looked at, shared, clicked on topics” associated to Hondas, Grant said.

So Romney’s debate could also use ShareThis to aim people who were reading or pity calm about Obama, or about Obama and certain subjects, like medical or a economy.

“It would be intelligent for him to do,” Grant said, generally if a Romney debate was perplexing to strech uncertain voters.

ShareThis is clever to stay divided from some tracking. It doesn’t accumulate a information users form into web forms, even yet that’s a capability other tracking companies have.

The association also chooses not to compare a information on users’ browsing habits with their real-names or offline sources like voter records. They also won’t bond your genuine name to your online interests, even if we record in to ShareThis around Twitter or Facebook.

Earlier this month, we wrote about how Microsoft and Yahoo use registration information (like names and Zip codes) to match Internet users to their central voting records, so domestic campaigns can aim ads to sold people formed on their celebration registration or concession history.

Grant called that “a sleazy slope,” and pronounced that ShareThis elite to keep a information on sold people totally anonymous.

“Even if it is relating information that is one step reduce than anonymous, to me, it’s not a protected place to be operating,” he said.

It’s value observant that Tim Schigel, ShareThis’ owner and chairman, is a tip record confidant to a Republican National Committee, where he consults on a far-reaching operation of issues. (“Tim’s purpose on a RNC doesn’t have any temperament on ShareThis. ShareThis is a vast height that runs ad campaigns for possibilities opposite a domestic spectrum,” a association mouthpiece said.)

All this information was useful — though it still didn’t answer one slow question. Was a strain that we had searched for on Grooveshark, Pink’s “Raise Your Glass,” partial of a targeting process?

This isn’t a laboured question, given a Romney debate told a New York Times in Apr that Internet users’ low-pitched ambience indeed played a purpose in a campaign’s microtargeting research. Among other factors, people who like jazz were doubtful to respond to Romney ads, a debate discovered.

But ShareThis mouthpiece Jennifer Hyman pronounced that a association did not aim a ads “based on a song a user is listening to.”

So it’s still misleading whose domestic ads you’ll see if you’re too propagandize for cool.

We’ll be means to learn a many about how we were targeted if we take a screenshot of a advertisement, and another screenshot of a concomitant avowal message, and send them to us around email during targeting2012@propublica.org. Please embody a full URL of a page where we saw a ad.

Not certain how to take a screenshot? Here are a instructions if you’re using a PC, using a Mac, or using a smartphone.

You can also check out the “Message Machine” project, that is examining how campaigns are targeting electorate with opposite versions of debate e-mail messages.