As a non-native speaker (who does mistakes a lot), I think it's sad most sites (esp. forums - although it's tricky as it could be abused there) don't have an op

As a non-native speaker (who does mistakes a lot), I think it's sad most sites (esp. forums - although it's tricky as it could be abused there) don't have an option to select a mistake or typo and silently report it to the original text's author, with optional comments on what's wrong there. I only ever saw such things on news sites, where readers could report problems to the editors. So, many people see the mistake, but stay silent out of politeness or just feeling that it would be off-topic.