Seeking approaches to publishing recurring show and showtime information

A contributor in the syndication group aimed me towards RDF 1.0 in 
response to a question about an appropriate implementation approach for 
recurring radio show schedule information.

We currently serve an RSS .91 feed of internet radio shows. Each item 
is an instance of the "airing" of a show, at a certain start time, for 
a certain duration, at a certain url. A new item is created whenever 
an "airing" of a show is over, specifically, the next "airing" of that 
show. All kinds of interesting issues have been raised, and remain 
unresolved, as we've published this somewhat unusual RSS feed.

For example, often, the "posting" time of an item has little 
correlation to it's "next showtime". Some "next showtimes" are say, 
next hour, while others are, say next week. Unfortunately, the many 
aggregators and reader application or services treat the display order 
of the items quite differently. Some, in fact, "drop" the item as it's 
showtime approaches ... it was up there for 6 days, so it "expired", 
but the showtime was tomorrow. From one show/showtime item to the next 
show/showtime item (for the same show) we have changed (or not) the 
item title, and changed (or not) the item description. Not 
surprisingly, the different aggregators and treat these variants on the 
problem somewhat differently. Also, the databases of items that some 
aggregators keep and provide search against can be "polluted" with 
multiple showtime items of a single show.

I'm sure others have travelled this path before. Is there a generally 
accepted "best practice" for recurring show schedule information? Is 
there a treasure trove somewhere that summarized the behaviors of 
aggregators and viewers in this, and other areas? We're also 
publishing lots of items (50 or more) on some of our channels; should 
we limit it to say 15 to avoid making the above issues worse?

A pointer in the right direction would be much appreciated. Thanks in 
advance.

John

http://www.RadioShowLinks.com/
Popular Internet Radio Shows 
http://www.radioshowlinks.com/rss.aspx?id=11