I'd like to see a responsibility system put in place. Something like Stackexchange where it is easy to have an account, but you have to earn privileges to post or comment
According to this walkthrough of Stack Exchange, you first earn 10 by improving formatting or grammar in five posts. This gives "participate in meta", allowing you to ask for clarification of a site's scope, and "remove new user restrictions", allowing you to cite sources in questions and answers, provide screenshots in questions and answers if necessary, and answer protected questions. Then you earn 40 more by providing useful answers to a couple questions. This gives "comment everywhere".
In your vision of ResponsibleTube, how would a new user go about earning enough points to comment? Would initial reputation be based on an invite tree (like the field trials of Orkut, Gmail, and Google+), a valid enrollment in higher education (like the field trial of Facebook), a valid subscription to mobile phone service (like Yahoo! and current Gmail), or a months-long waitlist (like Google Contributor)?