What is RSS? It's "a format for delivering regularly changing web content. Many news-related sites, weblogs and other online publishers syndicate their content as an RSS Feed to whoever wants it."
As a reader of blogs, it's great to fire up the RSS reader to pull the newest content. It saves me a ton of time from having to check each site and see what is new. Most blogs have the RSS icon in the corner so you can easily subscribe.
For bloggers: You need to have an RSS reader - it should be a prerequisite to starting a blog. Too many bloggers are publishing the same content as other friends on the blog rolls. Ironically, the same bloggers that get pissed at magazine companies are usually the most guilty. No one's perfect, I know I've made plenty of netiquitte mistakes, but we need to do a better job. Taking a quick glance at the SportsCards Unscensored blogroll before you post something doesn't count. They have a great blog roll, but I'm pretty sure everyone is aware of the google blog roll delays.