I think <guelo>'s advice above is sound. I learned this lesson myself after testing early versions of http://recent.io http://recent.io -- there's a high barrie

I think <guelo>'s advice above is sound. I learned this lesson myself after testing early versions of http://recent.io http://recent.io -- there's a high barrier to convincing users to type in an email address and password, even if it's for personalized news recommendations across multiple devices. It's not necessarily a trust issue -- it's simply a hurdle. Fortunately there are other ways to do it...