This article has sat in the back of my mind for quite a while. It is one the major reasons I use Bloglines.
I doubt we are being inundated by them. One can always hope….
Glenn Fleishman has posted some analysis of the impact of RSS aggregators on his blogs’ bandwidth use. A well-behaved aggregator should always check to see if the file it’s after has been updated before it gets a copy of it, but lots of badly designed aggregators mindlessly pull the same file a couple times an hour (or more), and once you’ve got ten or a hundred thousand of these pointing at your RSS, going 24/7, it can get awfully expensive.