An RSS feed is simply a system that exports your posts/articles to whoever has signed up for the service.
It requires a "reader" at the subscribers end to "interpret" the data and show it as intended.
The actual feed itself usually comes as part of any blog package these days, so it's ready to go as soon as you are.
Now, I'll add some info from my own personal experiences...
1 - stick with a known platform like Moveable Type or Wordpress (and others). I personally use Wordpress because it sets up quickly on my server and has loads of nice templates available to get a look and layout you like.
I used to use a product called bblog, and it was great. But, it didn't allow certain tweaks easily to make things a bit more search engine friendly (Wordpress does).
I run a news blog that accompanies a main website. The site houses the static data, the blog is for news on the topic.
One thing to make sure you understand is this:
Just having the blog itself will not suddenly "make traffic" for the main website. In fact, the blog may take as much effort or more to update and maintain as the main website (assuming it even needs regular updating).
My reason for going the blog route was simple - I follow the topic anyway, so why not parlay that action into more content for my users. It's taken a while, but now the blog enjoys about 1300 visits each day - and generates revenue via the Adsense ads I have in place.
Adding a blog is a great way to spread yourself out and offer more to users, but in and of itself, it doesn't "make" traffic - it still requires you market it to develop it's own traffic, then careful placement of links will allow users to quickly and easily slide into the main website for the things that interest them.
I operate 5 blogs right now, plus one main website and a few smaller sites. the blogs take the most investment of time, but, IMO, are worth it.
Best of luck