If you could, could you refrain from posting an answer after the question has already been answered? If you posted 2 seconds after the first person it's alright, but an hour or so... That's considered spamming because it isn't adding anything new to the thread.
Here's an example:
Julie: Hey, what's the most expensive party hat?
Jack: The blue one is usually the most expensive.
Julie: Alright, thanks Jack!
Bill: Yep, the blue is the most, and right now it's about x million.
Julie: Really! Wow, that's pretty expensive! Ah well, thanks you guys!
George: Yes, Bill is right, blue is the most expensive.
Tom: wat he sed ^^^^^
In this case, George and Tom's posts (colored in green in this example) would be considered spamming... Bill's wasn't because he added something with the price.
If you just restate what was said above, it'll be treated as spam... Do it enough and it'll justify a warning.