Referrer Policy is a new HTTP header drafted in 2015, implemented last year. This header controls referrer header value browser sends when the user is navigating away from your website pages.
SiteGround is the best website hosting I have ever used, bar none. Dev4Press and few other websites are hosted on SiteGround Cloud server since January 2, 2016, and this review provides details about server performance and complete SiteGround experience so far.
Dev4Press server started experiencing occasional problems with overload in back in July. The problems started getting worse in August and September. And, the investigation lead to some interesting findings.
Developers know how to best use debug in WordPress and WordPress WP_DEBUG constant to get through potential problems and bugs their code might have. But, for regular users, using debug mode can be very confusing and can cause more problems than it can help solve.
Before we get to methods to fight comment spam, it is very important to understand how spammers and spambots work, what methods they use, what types of comments they are posting.