FeedWind - FeedWind is the world's leading RSS widget, Facebook widget and Google Calendar widget - works on any website and is fully customizable
Feedly - The content you need to accelerate your research, marketing, and sales.
Superfeedr - Real-time feed API - RSS and Atom over PubSubHubbub and XMPP. Superfeedr pushes RSS feeds in real-time for both publishers and subscribers, with open protocols and APIs.
FeedBlitz - FeedBlitz is a mega pack solution for social media marketing and RSS feed and subscriber integration.
Inoreader - Dive into your favorite content. The content reader for power users who want to save time.
The Old Reader - Read all your favorite online content in one place. Import your subscriptions in one click, find your friends, and start sharing.