KidsTube updated the site in July 2013. They changed the whole look of the website, and modifyed the signup process in order to comply with COPPA.
KidsTube now requires parent permission to join, which can be applied via the KidsTube Parental Consent form, Skype, or mail. Due to the long registraition progress, the site hasn't gotten as much activity as it used to. Also, every previously registered user of KidsTube in the past cannot upload or comment on videos until they send in parental consent, which alienated users away even more. There may be ways to bypass the consent, but they're currently unknown.