CatFeeder

CatFeeder is a WordPress plugin which allows WordPress administrators to create custom blog feeds by selecting the set of post categories to include in each one.

The Story
The idea for this plugin came due to some of the discussions amongst those who feed & read the Utah Open Source Planet. Many whose feeds are aggregated into this particular Planet write a wider variety of posts than just stuff about their open source activities. Some people felt that such off-topic material should not be pulled in while others like knowing a little more about each other and seeing that we're not all just about computer stuff.

The Need
Taking a look at some of the options already available, it seemed to me that none of them really fit the bill properly. The closest existing solution to this problem is to tell those who want to aggregate your feeds to use a URL like:

http://blog.example.com/feed/?cat=X,Y

However, this method means that if you choose to change your list of categories, you have to get everyone who aggregates each feed URL you have given out to update their configuration.

Advantage: CatFeeder
With CatFeeder, since you configure which categories' posts go into each feed, they never need to make such an update.

For example, you could create one feed for a Planet, another for members of a club you are in and a third for extended family to use.

Download
It's not available for download, yet. I'm working on it and expect to release it very soon.

About the Name
The name CatFeeder is a concatenation of Category Feeder.