RSS experiments

[Andrew Black (li)]

I am experimenting with XML::RSS to create an RSS feed.  Eventually I 
want to create a feed for what's new on a website but at this point I am 
just getting familiar.

I am using Thunderbird as the client to read the feed.   If I change my 
server to generate different data the client isn't noticing the change. 
I am presuming that it thinks that my data is the same as what it has 
already seen. So my question is - how does the client recognise that 
items in the feed are new items.
Any pointers would be welcome

Andrew