Rss Viewer

RssViewer displays RichSiteSummary syndication files in a flash .swf demo

Main features:

feeds and displays distant RssFeeds (syndication file)
support RSS 0.90+ and RSS 1.00+
support UTF8
database of your favorites NewsFeeds
OpenSource & free

http://www.erational.org/software/rssViewer/

Not all viewers are created equal

There exists multiple approaches to implementing a viewer. See http://www.gadgetopia.com/2004/09/23/RSSAggregationModels.html

It was said the LiveBookmarks, which have characteristics similar to a RssViewer, is very resource intensive.
read somewhere that a properly implemented RssViewer should only poll its sources no more frequent than once an hour. Some of these do it much more frequently.

See WebLog, EreaderRss