[OT] RSS and blogs: What exactly am I doing?

Sorry if this is too far off topic, but I couldn't find a suitable forum for it and since RSS uses XML (to some extent) I figured perhaps you guys would be more knowledge regarding my question.

So, my question is this. I notice a lot of sites providing RSS feeds and containing what they call a "blogroll" that somehow connects to another site, downloads who has updated their blogs when and then lists the names of their favourite sites contained within that list.

So, I've enabled my blog to keep an updated RSS page. Every time the blog is updated, an updated RSS page is created. But now when I go to a site like pingomatic.com, that will ping all of the related blog update sites, it only wants the blog URL, not the RSS feed. I also notice that weblogs.com (as an example) specifically states that it only deals with main URLs now and doesn't check RSS feeds itself (that might not be the best description of what it does, but you get my meaning I hope).

So now I'm confused about two things:

a) Why do I even need an RSS feed if people aren't even going to use it?

b) How exactly do these "blogrolls" work, where do they get their info from and how can I submit my website to these places that are queried for such information.

Again, I apologize if this is too far off topic. Perhaps someone could recommend a more appropriate forum for me to ask it in.

Thanks,
Gerb

Right, if no one else will answer it, I'll answer my own question now:

- The underlying idea is that RSS and pingomatic have NOTHING to do with each other.

1) You need an RSS feed to be picked up by programs like FeedDemon or by sites such as NetNewsWire (http://ranchero.com/netnewswire/). They work only with RSS.

2) Blogrolls can pull their information from files produced by either of the above services or perhaps by sites included in pingomatic. So, you should do both for your site: RSS and pingomatic (pingomatic is for people who can't/don't do RSS).

WordPress is one blog system that supports blogroll.