There's no hard definition but we could simplify it as follows: People who simply copy/paste the entire internet just to make a buck, are typically spammers. Their reasoning is that if they post more stuff, they may get more upvotes and make more money.

On the other hand those who take a long time to make their own content, or who may occasionally put a link or a meme that they like or find interesting, can't be considered spammers.