On the passive voice, see: http://languagelog.ldc.upenn.edu/nll/?p=2922 and many, many more articles on that blog.
On adverbs:
http://chronicle.com/blogs/linguafranca/2013/02/20/being-an-...
and on adverb hunting via software:
http://itre.cis.upenn.edu/~myl/languagelog/archives/004271.h...
and on this app:
"The Hemingway app is fun to experiment with, and it’s useful in that it calls out in your writing places of friction—allowing you to decide whether they are necessary or merely sloppy. No one is above clarity. And the app, based on the experience of running examples of my own writing through it today, is, like a good editor, attuned to the places where vanity seems to be getting the better of things."
Having said that, computer editing will only get better, until it is used seriously by professionals.
I noted that I thought the app's logic probably wasn't "up to scratch" as is --- I'm inclined to be a bit charitable, given the direction of the criticism the app's getting.
The irony here is that the beautiful name, "Hemmingway", leads people to paste bloody _literature_ into a style linter! You wouldn't even be able to hire an unqualified human to give you meaningful style feedback.
Nobody writing a novel should want this sort of thing. That's stupid. It's not for writing a novel. Verbal art is always going to break all the rules and invert expectations.
This would be like checking visual design heuristics against paintings or art photographs. Surprise surprise, they break your design rules!
Calling the app "Hemmingway" brands the app beautifully, and gets people engaged...unfortunately the engagement is jumping all over it for something it was never supposed to do.
I think there's good potential for style linting, it's a really under-explored area. And I think probably the app's rules, as implemented in this alpha, aren't that much up to scratch. You'd at least want to run a POS tagger, and probably a parser, to give better feedback.
So long as the heuristics are _correlated_ with common style problems, you can get some use out of the app. But apparently that's a difficult story to tell.