If a user is under 16, the user needs to get permission from a parent. Symbaloo does not appear to check whether a parent actually gave permission, though.
The item below could be okay, but the terms do not describe in detail what constitutes "submitting information" to Symbaloo.
"4.5. User retains any rights they may have in Information which is submitted to the Website. By submitting the information, however, the user grants to Symbaloo a perpetual, irrevocable, worldwide, royalty-free license to reproduce, adapt, modify, translate, publish, publicly perform, publicly display, and distribute the Information."
Note: Section 1d defines "user data" clearly, but that appears to be something different.
"user data: user-related data such as used links clicked, terms searched, origin, browser features, and log-in data;"