If you use LinkedIn, your email address can easily be exposed to anyone with access to a web browser, thanks to a Chrome extension called 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. Here's how Sell Hack describes the process:

The data we process is all publicly available. We just do the heavy lifting and complicated computing to save you time. We aren't doing anything malicious to the LinkedIn website. We think browser extensions are the best way to personalize an individuals web experience. We love LinkedIn and are trying to make it better for the community.

Update - March 31, 5:15 p.m.: In an email to BuzzFeed, LinkedIn spokesperson Krista Canfield wrote:

LinkedIn's legal team is delivering Sell Hack a cease and desist letter as a result of several violations.

LinkedIn members who downloaded Sell Hack should uninstall it immediately and contact Sell Hack requesting that their data be deleted.

We advise LinkedIn members to protect themselves and to use caution before downloading any third-party extension or app. Often times, as with the Sell Hack case, extensions can upload your private LinkedIn information without your explicit consent.