You are right in differentiating Spotback (content personalization) from Netvibes/Pageflakes (homepage customization). Spotback user experience, albeit not perfect yet, is designed to assist users discover great content without actively searching for it. In today's overwhelming amount of fresh news there is a growing need to offer alternatives to conventional news search and Spotback is aiming to do that by focusing on the RELEVANCY of specific news item to a specific user, rather than on the overall POPULARITY of the news item.