Final answer:
Inbox rules and spam filters enable users to filter email messages based on specific text strings or symbols, whereas email forwarding simply redirects received messages without content-based filtering.
Step-by-step explanation:
The function you are referring to is known as inbox rules or spam filters. These tools allow users to manage their email by creating specific rules that can automatically perform actions on incoming messages. For example, an inbox rule can be set up to detect messages that contain specific strings of text, commonly known as keywords or symbols, and then direct these emails to be discarded or moved to a different email folder. Spam filters utilize similar criteria for identifying unwanted emails and are often built into email services to protect users from spam and phishing attempts. While email forwarding automatically sends incoming emails to another email address, it does not filter messages based on content.