Sell Hack

The tool, first noticed by Yahoo Tech, is easy to install after a quick visit to Sell Hack's site. Once installed, a small "Hack In" button will appear on any LinkedIn profile. Users will then be able to dig up an email address associated with the user's account even if they're not "connected" via LinkedIn. A recent Sell Hack blog post notes that the site was created for marketing professionals "as an internal email finder tool for us to use when prospecting."

It's important to note that Sell Hack isn't mining LinkedIn's private data; rather it takes publicly available data (like name and work information) and then references that other publicly available data across the web to find an email address. In short, Sell Hack using is LinkedIn's brand and visibility to sell its data service.

While it's not uncommon for these types of email database mining tools to pop up in marketing and sales circles, Sell Hack's extension is unnerving due to the ease and, in our case, accuracy of finding a user's email address.

For LinkedIn, the tool feels even more troublesome given that, until quite recently, the company was the only major social network without a blocking feature. LinkedIn rolled out a member blocking feature back in late February, after numerous reports that the company's lax blocking policies were creating a "stalking problem" for some users.