You seek to understand what happens when the "Bypass Whitelist for Content" checkbox is checked.
The Web Gateway has a built in whitelist of reputable web sites that are known to contain safe content. Visits to these sites are not monitored or recorded and will be ignored by the Content Filter, allowing the Web Gateway to operate more efficiently and to focus the system resources on other content that may not be safe. By checking the box labeled Bypass Whitelist for Content Filter you can enforce the Content Filter operation on those whitelisted sites.
Please note that "Bypass Whitelist for Content filter" is unchecked by default. Please also note that the phrase "Content Filter" above applies to malware scanning as well as URL filtering.