A check has status "Whole content filtered (verify your filter settings)"
If a check has the status message "Warning: whole content filtered (please verify your filter settings)", then there is something wrong with your filter settings and WebSite-Watcher isn't able to detect updates.
Normally WebSite-Watcher compares the filtered textual content of the new version with the filtered textual content of the old version of a page. If the whole content is filtered, then WebSite-Watcher has nothing to compare and is not able to detect updates. In such a case this error message is displayed. Open the bookmark properties and verify/change your filter settings to fix that behavior. With the feature "Test filter" you can see the content which is compared to detect updates.
Related topic: What are filter settings (Overview).