Which MikroTik proxy feature is primarily focused on caching web traffic?

The correct choice focuses on HTTP caching, which is specifically designed to optimize web traffic. HTTP caching allows the MikroTik router to store copies of frequently accessed web pages and web resources in its cache. When a user requests a webpage that has already been cached, the router can serve that page directly from the cache instead of fetching it again from the internet, significantly reducing latency and conserving bandwidth. This feature is particularly beneficial for environments with multiple users accessing the same web content frequently, leading to quicker load times and reduced internet usage costs.

On the other hand, the other options, such as POP3, FTP, and SMTP caching, are not designed to handle general web traffic. POP3 and SMTP are focused on email protocols, dealing with the retrieval and sending of emails, respectively, while FTP is used for transferring files. None of these options are targeted at optimizing the delivery of web content, making HTTP caching the most relevant choice for caching web traffic.