Tech

"I AM continually shocked and appalled at the details people voluntarily post online about themselves." So says Jon Callas, chief security officer at PGP, a Silicon Valley-based maker of encryption software. He is far from alone in noticing that fast-growing social networking websites such as MySpace and Friendster are a snoop's dream.

New Scientist has discovered that Pentagon's National Security Agency, which specialises in eavesdropping and code-breaking, is funding research into the mass harvesting of the information that people post about themselves on social networks. And it could harness advances in internet technology - specifically the forthcoming "semantic web" championed by the web standards organisation W3C - to combine data from social networking websites with details such as banking, retail and property records, allowing the NSA to build extensive, all-embracing personal profiles of individuals.

Americans are still reeling from last month's revelations that the NSA has been logging phone calls since the terrorist attacks of 11 September 2001. The Congressional Research Service, which advises the US legislature, says phone companies that surrendered call records may have acted illegally. However, the White House insists that the terrorist threat makes existing wire-tapping legislation out of date and is urging Congress not to investigate the NSA's action.

Meanwhile, the NSA is pursuing its plans to tap the web, since phone logs have limited scope. They can only be used to build a very basic picture of someone's contact network, a process sometimes called "connecting the dots". Clusters of people in highly connected groups become apparent, as do people with few connections who appear to be the intermediaries between such groups. The idea is to see by how many links or "degrees" separate people from, say, a member of a blacklisted organisation.

By adding online social networking data to its phone analyses, the NSA could connect people at deeper levels, through shared activities, such as taking flying lessons. Typically, online social networking sites ask members to enter details of their immediate and extended circles of friends, whose blogs they might follow. People often list other facets of their personality including political, sexual, entertainment, media and sporting preferences too. Some go much further, and a few have lost their jobs by publicly describing drinking and drug-taking exploits. Young people have even been barred from the orthodox religious colleges that they are enrolled in for revealing online that they are gay.

"You should always assume anything you write online is stapled to your resumé. People don't realise you get Googled just to get a job interview these days," says Callas.

Other data the NSA could combine with social networking details includes information on purchases, where we go (available from cellphone records, which cite the base station a call came from) and what major financial transactions we make, such as buying a house.

Right now this is difficult to do because today's web is stuffed with data in incompatible formats. Enter the semantic web, which aims to iron out these incompatibilities over the next few years via a common data structure called the Resource Description Framework (RDF). W3C hopes that one day every website will use RDF to give each type of data a unique, predefined, unambiguous tag.

"RDF turns the web into a kind of universal spreadsheet that is readable by computers as well as people," says David de Roure at the University of Southampton in the UK, who is an adviser to W3C. "It means that you will be able to ask a website questions you couldn't ask before, or perform calculations on the data it contains." In a health record, for instance, a heart attack will have the same semantic tag as its more technical description, a myocardial infarction. Previously, they would have looked like separate medical conditions. Each piece of numerical data, such as the rate of inflation or the number of people killed on the roads, will also get a tag.

The advantages for scientists, for instance, could be huge: they will have unprecedented access to each other's experimental datasets and will be able to perform their own analyses on them. Searching for products such as holidays will become easier as price and availability dates will have smart tags, allowing powerful searches across hundreds of sites.

On the downside, this ease of use will also make prying into people's lives a breeze. No plan to mine social networks via the semantic web has been announced by the NSA, but its interest in the technology is evident in a funding footnote to a research paper delivered at the W3C's WWW2006 conference in Edinburgh, UK, in late May.

That paper, entitled Semantic Analytics on Social Networks, by a research team led by Amit Sheth of the University of Georgia in Athens and Anupam Joshi of the University of Maryland in Baltimore reveals how data from online social networks and other databases can be combined to uncover facts about people. The footnote said the work was part-funded by an organisation called ARDA.

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