One of the biggest problems with RSS for a dynamic site like Blogdex is that the content of individual entities will change over time. Over the course of a day, the description for a site in the top 10 may change up to 30 times as different weblogs link to the site and affect the ways in which it is being described.
This means that over many downloads of the Blogdex RSS feed, certain persistent links will be replicated many times. RSS 2.0 provides a facility to specify the identity of an item (it's guid), so that despite changing title and description, RSS readers should only keep one instance (probably the most recent). Some people have suggested a similar element for RDF, but no RSS readers I know of utilize this record:uuid element.
I am extremely busy this week, but I have changed the RSS 0.91 to be RSS 2.0 with the guid element in the mean time. As soon as my exams are over (April 2), I'll provide a facility for RSS 0.91, 2.0 and RDF. Please let me know if you have any suggestions/problems, as I'm excited to start providing more blogdex RSS features.