You can add an extension/plugin to your browser to make it easy to add rss/atom feeds to your Feedz account.
Awesome RSS for Firefox puts an RSS/Atom subscribe button back in URL bar. This will give you RSS and ATOM feed links that you can then add to your Feedz account.
RSS Subscription Extension (by Google) is recommended for the Chrome browser.
"This extension auto-detects RSS feeds on the page you are reading and upon finding one will display an RSS icon in the Omnibox, allowing you to click on it to preview the feed content and subscribe.
The extension comes with 2 feed readers predefined (Bloglines and My Yahoo) but also allows you to add any web-based feed reader of your choice to the list."