OT: This is the first time I hear about tab for a cause and it sounds very interesting. However, their Chrome plugin requests permissions to "read my entire browsing history". The privacy policy doesn't explain why this is needed, does anyone know?
The extension doesn't track your history (or even read from it, currently). We'll likely eventually implement a "Top Sites" feature that will replicate some of Chrome's new tab functionality, at which point we'll give users the ability to opt in to have the extension use their history to display their top sites on the new tab page.