Owning Rss Feeds Hands Down..

Here's the story: I have a Wordpress blog as a really big teaser for my sales page, as a channel through which I sell affiliate products and through which I sell a subscription service..BUT..is Wordpress even compatible with Rss feeding?

You see, I have this list of 55 Rss feeds sites but they keep saying "invalid url" (they don't accept a regular www dot .... dot com site? what's that about?), even after signing up for them, logging in and feeding again.

I know how powerful Rss feeds can be - it's checking out what's new on my site without actually going there..but other than that I don't know a darn thing about it.

So let's turn this into a RSS tutorial:
- Is it a smart idea to feed your URL to multiple rss feed sites, as in..55 of 'em?
- Is it a smart idea to feed multiple URLs to one Rss feed site?
- What about the URL itself: does it need to be an article, or can it also be an article category page or homepage even..and what are the advantages?
- Do feeds ever pop up in Google search results? A.k.a.: what's the use of and IS their any advantage in using RSS feeds if you want to get more traffic?

I hope someone here can enlighten me about RSS Feeds because they seem like a nice promotional tool, but maybe that's a bad assumption. Help this starter-up entrepreneur and I'll help you out!