RSS & Atom feeds

I have no idea what RSS and Atom feeds are…but I know they’re important to increase my traffic.

Can you explain what RSS and Atom feeds do…and how to implement them and use them optimally:

I’ve purchased the Arthemia Premium Theme which has a section in the dashboard to place Google Feedburner links (have no idea what that is)

But I’ve also downloaded some widgets that deal with RSS: KB Advanced RSS and Advanced RSS.

Is this overkill? Help!