The Wall Street Journal  recently reported on the collision of Nielsen, the media research firm, and the website PatientsLikeMe.com, an online discussion board support group for people with emotional disorders.  Participants at PatientsLikeMe discovered that Nielson had gained membership on the site in order to “scrape” the messages on the forums.

Scraping is an automatic, computational method for copying large amounts of data – like the content of a very large number of message board posts.  That kind of data in turn can be extremely valuable to market researchers who may want to monitor online “buzz” for their clients – including the manufacturers of drugs that the participants on PatientsLikeMe were discussing.  And the market for this service is booming as firms collect personal details from social networking sites and other online communities all over the Internet.

Keep in mind also that some of these sites may sell data about their users themselves, often promising anonymity, with no names attached.  However, it is well established that “anonymized” data very often isn’t anonymous at all.  Ten years ago, research showed that 87% of all Americans can be uniquely identified with only three pieces of information: ZIP code, birthdate, and sex.  And this issue came into the spotlight again recently when privacy researchers admonished Netflix  for releasing large amounts of customer data.

Sites selling data themselves might be covered in their Terms of Service, but what about these third-party market researchers – is scraping for your personal information legal?  Right now, the law is pretty unclear, especially with contradictory rulings on the issue in U.S. courts.  And scrapers and data brokers are arguing that any information that’s available online is fair game.

Particularly in online communities where sensitive topics such as medical issues are discussed, participants want to feel that their privacy is safe.  Though unfortunately this ties into a topic we discussed previously – beware of false friends  on the Internet.  Or at least, until there is some clearer legal precedent for the privacy of your personal information, beware that what you say online might end up in a company’s datasheet.