It is actually kind of hard to find information out there on rss feeds that explain what it is in regular people terminology. I am fairly new to rss feeds, but from what I understand, here's what it is.
RSS stands for Really Simple Syndication. If you sign up for my rss feed, you can have information from this site sent to various things that you already belong to. If you have a google or yahoo home page that you check regularly, you can go there to check up on what is happening with this blog if you have subscribed via a reader. I believe you can also have the rss feed sent to your social networking site (like myspace or facebook) and various other things. This option is really useful if you are already subscribed to a lot of updates from other sites. This allows you to have access to all your desired updates in one location.
The other option with an rss feed is to have a little icon appear on your toolbar with a drop down menu showing you the latest posts. If your toolbar is pretty clutter free, that might be a nice option for you, especially if you don't have a google or yahoo or other homepage at which you want to receive things.
If you prefer, you can just sign up for emails and then you don't have to deal with figuring out the new technology. You can sign up for emails and rss feed if you want. Or, you can bookmark this page and just check back whenever you feel like catching up on posts
Now, with all that said--Feel free to correct me or add to my definition in the comments section.
Hope that helps!