Thanks! Scoble is obviously very excited about social media ("we are heading into an age of predictive services based on our identity"), which is fine - I still see it as a trap and not an exciting future - but even if I, and others like me, accepted social media I think LurnQ would see usage go up if the sign-in were simply optional (ie, if they placed the login below the content). (I also understand that that may seem like extra work if all the features are "best" with the social parts... But by not doing so, the non-facebook crowd - which includes the impatient and not-logged-in - simply press X.) Take Khan Academy, for example: you can watch the videos and explore but login to get the features that depend on tracking through time.
The core value proposition of Khan Academy is the content they produce which is amazing stuff. LurnQ on the other hand is a consumer tool that aims to simplify online learning. It helps you manage your learning in the open learning ecosystem. It i somewhat like GitHub for learning and unless you signup the experience can not be delivered.