Sharing a link to a social media website using a plugin? Prepare to lose privacy. But this time it's not the NSA tracking you. Instead you're being tracked by the plugin vendors. Vendors like AddThis, ShareThis and AddToAny are keeping track of what links you are sharing, not only on the current website, but on any other websites that use those plugins.
But they don't really know who you are, right? You've never given them your Facebook ID or Twitter ID. Well think again. These social sharing plugins are using by millions of websites out there. Even if you don't click on them, they are still being loaded by your browser whenever you visit a page that uses social sharing plugins, allowing them to track you by your IP. And by constructing a huge database of websites that you've visited, they can generate a pretty clear picture of your personal interests and browsing habits. Information that advertisers and insurance companies are interested in.
Not only can they track you, they can also track the people who visit the links that you've shared. Some plugins will modify the link that you share to include a tracker ID or will substitute another link that redirects the user through another server first. This way they can build a database of people who share things and find out who clicks on those links and who subsequently re-shares them.
And think they can't track you because you're using Incognito mode or InPrivate mode in your browser? Well AddThis is experimenting with a new tracking tool called Canvas Fingerprinting which is virtually impossible to block. It works by picking a bunch of metrics off your computer, including things like what fonts are installed, and then generates a unique fingerprint of you on this particular computer. Even if you clear your cookies or block them, they can still track you.
How about "opting out" of being tracked on the social sharing plugins website? Many social sharing plugins feel obliged to offer you the ability to opt-out by setting an "opt-out" cookie in your browser. This is the real world equivalent to sticking a "No Spam" sticker on your mailbox at home. But lets face it, how much do you trust them to comply with those cookies? They didn't ask you for permission to take part in the Canvas Fingerprint experiment in the first place.
Well what can we do?
For starters you can send an email to your favorite websites politely asking them to stop using social media plugins that track users.
You can also write to your senator asking them to support laws that protect your privacy.
If you own a website, you can use Open Source social sharing plugins that don't track users or use plugins that can be whole hosted on your own server and that doesn't call out to external servers.