When I visit the root domain I shouldn't be greeted with a marketing splash page, you need interesting content in the user's face right away, entice their curiosity and drive the user to explore the site... even as a fellow developer, my first instinct is to abandon the page as soon as I'm greeted with the cliche startup marketing page. Consider the user experience when I visit reddit.com or news.ycombinator.com or any other link aggregation competitor. What you have now is a tech demo, not a platform. Sorry if that's a little harsh, but I mean well! Good luck!
My original plan was to pay for ~100 users accounts and seed the site with content for a proper launch. Given what's happening today though, it felt at least pertinent to show off the current state and get some feedback.
The balance between splash page on landing / landing on content is a hard one, but I think you're right. I am worried though that without conveying the initial business model, it'll be harder for users to understand that this isn't a direct reddit clone.
So basically what already happens with reddit/twitter/etc but amplified because you give them a direct financial incentive to upvote low effort crap.
I think the problem with karma/reputation systems is that the source of karma are fungible - anyone's upvote has the same effect on the reputation. And this makes it gameable.
A personalized system can solve this by replacing global reputation with user-to-user trust. Now it matters who upvoted - a random bot or a user whose past contributions have been useful to you.
In that system how do you create a ranked list of content for a user to browse? Isn't it going to be very heavy on processing demand?