So I've been on Reddit for about 7 years now. I'm a moderator on several popular boards, including /r/Veeky Forums. I will try to give you guys an unbiased, objective outlook.
Reddit's main problem is its karma system. It encourages users to post content which the majority will agree with rather than something that may be controversial (but still contributes to the conversation). Because of this, most communities become predictable and boring.
This is the lifespan of a submission on your average default subreddit:
- 1 minute in: your submission will most likely be downvoted into obscurity. The reason behind this isn't necessarily because your submission sucks, but there are other people who just made submissions and are downvoting every other new submission in an attempt to have theirs noticed quicker.
- 10 minutes in: if you managed to survive this far, your submission may start picking up steam. You'll see the first comments start to roll in. They will be mindless, vapid, and generic things like "omg i spit my coffee out after seeing that!" The reason there is no effort put behind them is that they want to be the first to post before everyone else. The sooner you post, the more likely your comment will be seen and upvoted.
- 3 hours in: whoever managed to comment first on your submission will now be the highest voted comment, regardless of how little it contributed to the conversation. Since your submission will have so many comments at this point, more people will start replying to the top comments. The reasoning behind their comment will likely be noticed quicker, leading to more karma for their account. These replies are just as vapid as the original comment. Pun chains are very common. Remember: as long as they get that reply before other people, they're more likely to get upvotes.
- anything afterwards: barely any comments are posted, because why even bother? Their comment won't be seen under the mass of thousands of other posters.