When adding a blacklist URL to block a site, user are still able to get to the site even though you have blacklisted the site. When adding a whitelist URL to allow access to the site, user are getting blocked to the site.
"Customers have reported issues with using the Blacklist and Whitelist feature of SWG when attempting to create policies related to top-level domains (TLDs). Top level domains are specific to the suffix of the URL (ie. .com, .us, .ru, .cn, ect). The Blacklist and Whitelist features are intended to enable polices against specific web sites and domains, and were not intended to create blanket polices for top level domains. When polices are created using TLDs, customer have reported inconsistent behavior and performance degradation. Due to these issues, the SWG GUI will be modified to not allow TLDs to be entered for Blacklist and Whitelist entries."