Back in the early days of RSS, webmasters used to link to their feeds using little rectangular orange buttons labeled “RSS” or “XML”. Then along came Mozilla Firefox, the web browser that re-started the Browser Wars. Since Firefox had RSS support built-in, the developers created a cool new icon to use in the browser: An orange rounded-square with an odd symbol on it. The symbol depicted an antenna. Since then, the Firefox feed icon has become the standard one used throughout the web. There’s no confusing it with anything else.
Grab a copy of the “Standardized Feed Icon” at FeedIcons.com They offer a .ZIP archive with different sized and colored variations of the image. Several formats are available in the package. There’s PSD, AI, EPS, SVG, PDF, PNG, JPG, and GIF. Get the standardized feed icon for your site.