If you have created one RSS feed for your news group or web blog or for anyother purpose then it is your responsibility to ensure that your RSS feed file can be parsed by the XML parser of any subscribing site.
Many of RSS feed creation softwares validate XML at the time of feed creation but some don not do. Make a note that small errors can make your feed unreadable by the standard feed readers.
So I would suggest you before publishing your RSS feed make sure you have done all the required validations. You may wish to load your RSS feed file to your internet server and then enter the URL in one of the following validators to check the syntax.
Feed Validator - This validator validates multiple syndication formats: RSS 0.90, 0.91, 0.92, 0.93, 0.94, 1.0, 1.1, and 2.0. It includes validation for common namespaces.
RSS Validator - If you are using RSS 0.91 or RSS0.92 then you can use this validator to validate your RSSfeed.