Clearspring Not So Clear on Privacy

Clearspring Technologies is using its "Add This" button to follow people and sell the resulting data to marketers. " The button allows users to alert friends and contacts to interesting or useful material on the Web. For instance, with a click, a news article could be sent to a friend over email or posted to a site like Facebook Inc." Critics, however, see the activity as a secret way to intrude on people's privacy.

Some industry practitioners have no qualms about the practice. "There's a new sharing economy," says ShareThis CEO Tim Schigel," another firm that carries it out.

- From Emily Steel, "As Web Surfers Share, Marketers Track," Wall Street Journal, August 19, 2010