I think sharing original content is seen as egocentric, as you're the only party involved, and sharing content from someone else is seen as selfless. Originally, that might have been the case: why would you share an article written by someone else unless you're really convinced it was important to the community? But Reddit introduced the karma system: now, when you submit non-OC, you get some benefit out of it too. Granted, it's only imaginary internet points, but enough people care about it to make it work. When you submit OC, you're getting all the attention, pageviews and karma. You can't have your cake and eat it too.
And ad dollars, increased reputation online, SEO backlinks, etc. There are a lot of reasons that reddit doesn't like it. Their subreddit / moderation system is set up to fail in terms of preventing sites from gaming the system. Anyone can submit anything to any subreddit at anytime and it will get clicks from the subscribers of that subreddit. Here (and on places like twitter) spam is only seen if they are shared by the community. So if your post is worthwhile, it will be shared, and it's no longer an egocentric endeavor. Spam and worthless posts are very rarely viewed or clicked if it is posted by someone with no one following them. Because of this, making an account purely to show your spammy site and then creating 10 more accounts to share that spammy site still isn't going to have an affect on the community. In order to be successful users would have to follow the spam user or follow someone who shares the spam post. Both of these things can be instantly avoided by unfollowing, ignoring the user, ignoring the domain, etc. We haven't had a influx of comment link spam (*knocks on wood*) but the same ignore user function would work and there is also the mute function. There is a huge difference between sharing something that you've written and you want to discuss and enjoy with your audience and spamming your ad filled space. Hubski works because (1) we have a demographic of intelligent and thoughtful users who know the difference between spam and original content (2) the ability to ignore (and mute!) users who post content you don't want to see. The amount of karma/clicks/ad dollars/etc you will receive is based on the quality of your post. If you want to spend a lot of time writing something that is intriguing, posting it here for us to read, and making it worthwhile enough for me to share it, then go for it. I don't mind if you get a few bucks from my click or some internet points.When you submit OC, you're getting all the attention, pageviews and karma.