Well, to answer your initial question, RSS is XML, meaning for the most part it relies on serving the entire document every time to create a valid feed file. As such, as the number of articles grows, every request for the feed grows in size. So clipping it to the latest stuff helps relieve load on the server.
RSS is also commonly used to serve podcasts, and I've been told by a number of podcast hists that they like this because it prevents someone from sticking the RSS in their podcatcher and blasting the server with requests for every episode all at once.
I'm guessing that a lot of RSS generators have this as a default, and many of the people with their RSS set up like this simply never change the default.
RSS is also commonly used to serve podcasts, and I've been told by a number of podcast hists that they like this because it prevents someone from sticking the RSS in their podcatcher and blasting the server with requests for every episode all at once.
I'm guessing that a lot of RSS generators have this as a default, and many of the people with their RSS set up like this simply never change the default.