RSS (Rich Site Summary / Really Simple Syndication) is a lightweight XML format for distributing news headlines and other content on the Web. You point a RSS-capable browser at the RSS link for a website, and you can then subscribe to the feed, seeing the content within an RSS view in your browser.
I liked the idea of it for being able to keep up to date with my favourite news blogs and sites, but I never really managed it very well, ending up with way over 80 bookmarks in Safari, in different folders on my bookmarks bar, making it a little difficult to keep up to date with new content.
Introducing Vienna:

Vienna is a really simple yet powerful RSS client for Mac OS X.
Vienna takes away all the complications with dealing with a lot of RSS feeds, by allowing you to subscribe to them all from one place. It allows you to create folders for different categories of feeds, and automatically checks for and downloads updates at a regular interval you choose.
It has some powerful features for finding the content you want, by allowing you to create Smart Folders of feeds, that automagically update as you would expect from any self respecting Smart Folder.
And because the content Vienna downloads is cached, you can then view your RSS feeds offline, ideal for people who have a lot of feeds to keep up to date with on the move; connect to your hot spot at Starbucks, let Vienna update, then disconnect to save your bandwidth.
To set it up, you simply drag any RSS bookmarks you have into it’s sidebar, and you’re done. Vienna will then automatically check for updates to the feeds for you, and notifies you when there are new ones by displaying an indicator on it’s dock icon, much in the same way that Mail.app does.
What I like about Vienna the most is that is isn’t trying to be anything other than a feed manager – a lot of applications I’ve seen try to do so much they actually end up being browsers in their own rights, but not quite as good. I’m happy with my browser, so I want to stick with it, I just want a nice centralised place to keep up to date with my feeds – Vienna does this, and does it well.
Vienna 2.1.1
Link: http://www.opencommunity.co.uk/vienna2.php (1.3MB zip)
Reqs: Mac OS X 10.3.9 or later (Universal)