I was just thinking that some of us may blog broadly, on many disparate topics, and thus get a few different readerships. Some bloggers may blog on Entertainment, Sports, Politics and Education, for example. However, a reader may only want to read the articles from Entertainment, Politics and Education, or just Entertainment and Sports.
Therefore, I feel it would be better if WordPress came up with a simple widget that bloggers can choose to put up on their sidebar. Using a simple checkbox form, readers can filter the categories they want to read.