Today I'm sharing a great tool for exploring typography on the web. Fontface Ninja is a plugin for the Chrome and Safari browsers that allows you to identify the font face and styling of any text on a page. Simply mouseover some text and Fontface Ninja will bring up a slick animated tooltip that tells you what font is being used, its size and line height in pixels, and what (if any) custom letterspacing has been applied.
The plugin also provides the option of viewing a page stripped of all of its colors and images, showing just the text of the page in black against a white background. Clicking on the tooltip brings up a field box that allows you to take the site's font for a spin; you can type some text in the font (whether the font is already installed on your system or not). Finally, for sites that use webfonts, you can even send your font ninja on a secret mission to retrieve and download the entire font. As the developers point out though, the plugin isn't an open invitation to steal fonts from type designers: if you like a font and plan to use it in one of your projects, you should always get a legit copy and license.