Like Twitter, long-standing site-recommendation service StumbleUpon collects data about your visits across a big network of sites that feature StumbleUpon widgets. Also like Twitter, StumbleUpon now recognizes the Do Not Track signal when you enable it in your browser. This is another good sign of momentum for Do Not Track compliance.
Here’s how StumbleUpon explains it:
What does this mean for StumbleUpon?
When you turn on “Do Not Track” in your browser, StumbleUpon stops collecting the information that allows us to recommend what’s best for you based on your recent visits to websites that have integrated our badges or widgets.
We do this by removing the cookies saved to your browser when you visit certain websites linked to StumbleUpon Services. StumbleUpon will still provide you with personalized recommendations based on your interests and Stumbling history, but without this extra browser information.
I’m a fan of this approach in part because (like Twitter) it promises to block collection of data and not just its use (a distinction at the heart of the Do Not Track definitional debate). One gripe is that the language doesn’t specifically confirm that Do-Not-Track prevents collection of anonymous data for sharing with advertisers (rather than stumble-recommendations), something StumbleUpon reserves the right to do in their privacy policy. This is unlike Twitter, which so far only allows use of cross-site data for recommendations, and not for ads.