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The most common reason is that people enter the URL for a web page rather than an RSS feed. The app will detect that and scan the page but sometimes those web pages, despite listing feeds, don't declare them in the standard way for readers to detect. Try to open the feed in the browser, then select "Share" from the browser menu then "Add a new feed" from the share menu.
The app does a number of things to get a good favicon, including checking both the feed metadata and the root website for a good favicon. However, if the favicon is low quality (will appear blury in the app) it is discarded. At this time, you can not select your own favicon.
From the browser, log in to feedly.com. In the green bar on the left side, select "Organize". Scroll to the bottom and select "Save as OPML". In RSS Savvy, go to "Manage Tabs" and press the "Show Import / Export Options" button. From there you can select the OPML file you just saved.
Open FeedMinder for BlackBerry, select "Manage Tabs" from the menu, select "Show Import/Export Options" and select "Export Subscriptions to File". After saving to file, you will be prompted to Email the subscriptions as an off-device back-up which in most cases, is the simplest way to transfer the file to your other device. From your Android device, save the file you just emailed to yourself. In Android RSS Savvy, select "Manage Tabs" from the menu, select "Show Import/Export Options" and select "Import Subscriptions to File" and open your saved subscriptions.
Exporting subscriptions from the BlackBerry version of RSS Savvy is not possible - this feature is only available when you upgrade to FeedMinder.