Good Day,

Is it possible to setup a system with RouterOS and use the hotspot feature to make users login, and be able to firstly track what URLs they go to, and secondly to block certain URLs?

For example, BrightCloud has a system where URLs are classified into certain categories, we'd like to block requests to certain categories. Is this possible with RouterOS?

Thank you!

Hardly. Manually, sort of. You don't want to classify all web sites on existence, that is hard work. Use something like OpenDNS for free filtering. Not great, but free.