What is the difference between feeds of RSS and atom?

A reader asked..
I am using Google reader as a feed reader and I think it's the BEST then any other reader. But on may sites there are 2 option are available for feeds 1st is RSS and 2nd one is atom.

So I want to know that what is the difference between RSS and atom feeds?

(Scroll down to read responses).

Related Stuff:

Londons Times Funny Aliens Cartoons - When You Get Lost Between The Moon And NYC - Coffee Gift Baskets - Coffee Gift BasketWhen You Get Lost Between The Moon And NYC Coffee Gift Basket is measuring 9x9x4. Contains 15oz mug, BONUS free set of 4 coasters, biscotti and 5 blends of gourmet coffee. French Vanilla, Kenya AA, Decaf Colombian Supremo, Chocolate and Italian Roast Espresso elegantly presented in our signature black planet coffee gift box. A very nice and thoughtful gift for any occasion.

Girls Tennis Skirt and Shorties by In-BetweenMicro-Tek Supreme 90/10% Meryl micro-nylon Lycra - Inspired by our Womens' line, we offer our Pull-on Skort with attached Court Shorties. 2 easy access ball pockets, 12' Inseam and side vents. Comfortable fit for that sporty look, on or off the court. Featuring Body Care, moisture wicking fabric that has a rich, cool, silky hand with important SPF 50+ protection, ease of movement and shape retention.

Ju-Ju-Be BeTweenNot too big and not too small

Chocolate Passover Seder SymbolsFour Dark Chocolate cards molded in the shapes of different Passover Seder Symbols. Packed in a clear top gift box.

My Pony ClubManufacturer's Description: Start off by creating your own pony & you can choose the color, the tail, the mane style and the breed. You will have to look after your pony making sure it is properly fed and that its stable is nice and clean. Help Marie compete in a variety of tournaments, including show-jumping, dressage and cross country. But beware there are lots of riders who also want to win the first prize rosettes, and they'll do everything they can to make sure you don't win!

Share and Enjoy: