Be careful, they aren't kidding when they say "Nitpicker". Many of the mistakes covered (for example while/whereas) are extremely common and are acceptable in all but the most stringent circumstances.
Sure, but I can still make up my own mind in those cases. For example, I don't see myself saying "do not" instead of "don't", but with while/whereas, I'm happy to have that pointed out.. It never occured to me, because I learned and learn English from reading/hearing English, so it's very easy to pick up sloppy habits. I think "whereas" is a neat word and should be used more often, at least by me :)
As Orwell said: "If people cannot write well, they cannot think well, and if they cannot think well, others will do their thinking for them." I like nitpicking, I love being corrected. But maybe this would be even better as a list instead of an online application.
