Yeah, RSS feeds are baffling -- until you find out how useful they are
You don't need a separate reader if you've got Tiger, as RSS is built-in to Safari 2. A lot of people complain that Safari's support is very limited, and the fact that I find it adequate probably means my understanding of the capabilities of RSS is limited!
Here's one of the ways I use RSS...
Bring up a news site, such as cnn.com. At the right side of the address bar you'll see a blue "RSS" icon. You also may see them embedded in the site, often times tied to a specific feed (such as Entertainment News, or Travel News). Instead of a blue RSS icon, you may see an orange square icon with three white semi-circles, or a rectangular icon that says "XML"
Click on one of those, then bookmark it.
Go to another news site, such as bbc.co.uk -- bookmark one of its XML/RSS feeds. Add a few from the New York Times, Washington Post, and any other sites that have news of interest. Now organize your bookmarks, create a news folder, and add all of these RSS subscriptions into that bookmark. Drag the folder to Safari's bookmarks bar.
Select the news folder, and then select "View all RSS articles" You now have all of your news on a single web page. On the right-hand side is a search box. Now type in something such as "London" or "Apple". You now have a page full of news headlines about London or Apple (or both if you want). You can now even select "Bookmark this Search" from the action bar on the right, and any time you want to see news about Apple combined from a multitude of sources, just click on this bookmark.
Don't forget to select some of the options on the RSS tab of Safari's preferences.
There are also various other ways of reading RSS feeds. I have a few widgets that pull information from various feeds. There may even be growl notifications that can be set to alert you when there's new news.
I'm sure others here can give some even better ideas about creative uses of RSS.
Saying an RSS feed is like a textual podcast is really kind of backwards. Podcasts are really audio RSS feeds, since the method of delivery is based on the same technique.
Hope this helps, and hasn't simply confused the issue even more!
BTW, in my Safari browser are the following RSS subscription categories: Friends Blogs (with a single click I can see what all my friends are up to), News (detailed with way too much verbosity above), Apple (News from a few Apple-specific websites), A real-estate feed (keeping an eye on housing in Seattle), cycle information from craigslist (so I can see what's for sale and search it offline easily).
Any time you see that "RSS" icon in your address bar, you've got a page that can be viewed as an RSS feed by simply clicking on that icon.
Have fun!
P.S. If you don't have Safari, you can check out
NetNewsWire Lite. It's a free RSS subscription tool. They have a paid version with more features...