Spam is one of the first slang words ever invented that refer to an activity on the internet.
In 1937, the Hormel Foods Corporation introduced a new kind of canned pork that was called Spam. After World War 2, Spam became a common household item, so much so that the British comedy team Monty Python wrote a popular comedy skit about it. The punch line of the skit involved replacing all of the items available on the menu at a diner with Spam, leading to the diners repeatedly chanting “Spam! Spam!”
Today, the food product is now called SPAM in order to distinguish it from spam (all lowercase letters), the internet phenomenon involving sending unwanted messages in bulk
For WordPress specifically, spam usually comes in the form of unwanted comments in bulk that are posted automatically via computer scripts. In other cases, spam on a WordPress site can be computer scripts registering fake users in bulk or filling out contact forms with nonsense or irrelevant messages. But because WordPress is the most popular blogging software in use on the internet, the term spam usually refers to comments.
The content of a spam comment is usually off-topic and may contain one or more links to affiliate advertising sites and/or low-quality, illegal, or unethical websites. Since the spam comment is not relevant to the issue being discussed and the links may cause harm to anyone who clicks on them, spam comments can quickly make your website unattractive to visitors. Furthermore, search engines may interpret spam comments to be of low value and so penalize your website for allowing this content to appear.
When you install WordPress, it comes with a built-in plugin named Akismet that is specifically designed to reduce comment spam. To activate Akismet, you’ll need to create a (free) account with Akismet first.