Or, put another way, that I'd understand.

An icon is a picture that represents a computer program you use - like the blue W inside the squre that represents the Microsoft Word program.

An Avatar is a picture that represents a person. It is usually a human form but I'm hearing it more and more to represent any picture that represents a person on a board. For example, on another board, mine is a small green dragon.

An emoticon is a picture that represents an emotion. They are often a play on that 1970's smily face. Now the face smiles, frowns, cries, throws up and all the other emotions we go through. When you see it, you know exactly what the person is feeling. There are also new types of emoticons, like alien faces and such. Some though, are not as evident when seen by themselves, but make perfect sense when following to a sentence.



EDIT: Ooops, sorry jheem, I hope I didn't insult you with my first sentence. I know what icon, avatar and emoticon mean, but I have to admit that if I didn't know I'd be a little confused by your sentence. Which is why I wrote it in the way above.