Akismet is a very well known anti-spam plugin for WordPress created and maintained by the folks at Automattic (the developers of WordPress.com). The plugin was created to allow bloggers and site owners to quickly protect their comments from spam without having to manually approve each comment before publishing. According to WordPress.com's official website, Akismet is by far their most successful and popular product. When you install the plugin and activate it on your blog and site, all your user comments are scanned with an anti-spam algorithm that consists of a black list (text patterns used to filter spam) and a white list (words from which to build whitelists). The best thing about the service is that it does not just stop at just checking for spam but it also helps you catch comment/email spoofing as well as trackbacks originating from illegal sites or spammers sites hosting malicious scripts.

Akismet is used by over 5+ million blogs and websites to protect the comments on their sites against spam.

Akismet was created by Matt Mullenweg in the year of 2005.