It's annoying to see people repost whole articles that they found online. A character limit would make people get to the point, and if they want to post something they can post a link. If someone really is interested they can click the link. I'm not suggesting 50 characters per post, but just something to limit people from posting full articles that you have to scroll through to get to other opinions. Rarely do people post over 1000 characters anyways. Also you should block the same IP from posting twice in a row.
Just some thoughts.