A news aggregation website with upvote/downvote and user reputation. (reddit for news)
MVP: 9headlines.com. (currently I'm aggregating news from Indian sources only)
I'm also working on a user reputation system to reduce spread of misinformation and fake news.
I'm not a big fan of the 'upvote/downvote' system myself, although I do understand how it makes sense to implement. At the very least, I do think, keeping the downvote data private is better.