I think an optional spellcheck/grammar setting would be amazing. Pre-release of a blog it'll go into a special mode where certain people can read your blog and fix any spelling/grammar mistakes you may have made.
This would really help non-native English speakers get their point across and also help them in learning the language at the same time. I've seen too many brilliant blogs not getting the traction they deserve just because their English isn't the best.
Maybe add badges or some kind of incentive to get people to actually bother!
I'd love to hear people's thoughts on this and also hear some features you'd love to see on the website!