There’s plenty of discussion these days about what a bandwidth hog RSS has become. Robert Scoble provides a decent explanation on why this occurs:
20% will leave their aggregator on all day long pulling down the feed once per hour (200 people x 24 pulls a day x 30 times per month) = 144,000
20% will leave their aggregator on at least one hour a day, pulling down the feed at least once (200 x 1 x 30) = 6,000
30% will leave their aggregator on at least a few hours a week (let’s say five hours) (300 x 5 x 5) = 7,500.
10% will only pull down their feeds once per month (let’s say five hours a month) (100 x 5 = 500).
10% won’t turn their aggregator on at all.
In short, be responsible with how often your RSS reader pings subscribed feeds.
DarrenBarefoot.com 
And don’t forget to plug bloglines.com
http://www.bloglines.com
Chris
I don’t think I get enough traffic to even matter. The four people who probably do read me can ping all they want!
I run Sage (firefox extention)and manually check my feeds 3 times a day. I think I’m like a lot of people who run rss feeds. Run the feed see if anything new is on the site or anything catches my eye go to the site if the rss feed only has a 10 word blurb and no content. Lot of rss feeds, including mine, contain full posts right in the feed itself. He didn’t make that distinction in his “findings” before using rss feed I would go to those sites the same number of times. Now the plug in does the checking for me automatically. I’m not so sure his arguments were completely thought out.