My fiancee, Soosun, is brushing up on her English skills before going to uni next year. As part of the plan to improve her writing, she's started a blog. Friends and family can write comments on her posts to help improve her written English.
She just wrote a nice article on making kimchi, and I posted a comment containing a copy of her article with English improvements. But how can she tell what I've suggested? The solution we decided to use is kdiff3, a tool I use at work for comparing and merging source code. You can download it here. If you turn word wrap on, it is great for comparing English - shows up the differences beautifully.