Your assumption is correct, user retention is difficult. I've been running LinkLonk for a year now and out of >1000 users that created accounts we have ~9 daily

Your assumption is correct, user retention is difficult. I've been running LinkLonk for a year now and out of >1000 users that created accounts we have ~9 daily active users on the site and 43 users are getting recommendations by email. But I think this is in part the chicken and egg problem. The more users join the more useful the system should theoretically become. If you don't want to create an account, consider creating a guest account - it does not require any personal information from you. The account is just a number that is issued to you and is stored in your browser cookies. If you don't end up using it - all information associated with your guest account will be deleted after 30 days of inactivity. If you don't want to create a guest account then the best I can do is to show generally popular content - which is what the home page is filled with for brand new users.