Blade is a blogging tool and a content management system.
Simple, lightweight and highly customizable.
Auto tagging for plaintext and code.
Comment reply look-up.
Comment with basic HTML tags.
Widgets are part of Blade. Some widgets written by the author are builtin. However, you can write one for yourself, too. The author has provided a simple template, as can be seen in the source of each widget.
Plugins are not part of Blade. These include but not limited to reCAPTCHA, SyntaxHighlighter, etc. The copyrights of plugins are their respective owners.