Google's John Mueller covered lots and lots of myths this past Friday in the Google Hangout on Google+. He said at the 34:37 minute mark that having short articles won't give you a Google penalty. He also said that even some long articles can be confusing for users. He said that short articles can be great and long articles can be great - it is about your users, not search engines.
The question posed was:
My SEO agency told me that the longer the article I write, the more engaged the user should be or the Google will penalize me for this. I fear writing longer articles with lots of rich media inside because of this, is my SEO agency correct or not?
So I really wouldn't focus so much on the length of your article but rather making sure that you're actually providing something useful and compelling for the user. And sometimes that means a short article is fine, sometimes that means a long article with lots of information is fine.
So that's something that you essentially need to work out between you and your users.
From our point of view we don't have an algorithm that council words on your page and says, oh everything until a hundred words is bad everything between 200 and 500 is fine and over 500 needs to have five pictures. We don't look at it like that.
We try to look at the pages overall and make sure that this is really a compelling and relevant search results to users. And if that's the case then that's perfectly fine. If that's long or short or lots of images or not, that's essentially up to you.
Sometimes I think long articles can be a bit long winding and my might lose people along the way. But sometimes it's really important to have a long article with all of the detailed information there. That's really something that maybe it's worth double checking with your user is doing some a/b testing with them. Maybe getting their feedback in other ways are like sometimes you can put like the stars on the page do you have a review that or use maybe Google consumer surveys to get a quick kind of a sample of how your users are reacting to that content. But that's really something between you and your users and not between you and and Google search engine from that point of view.
I specifically did the Google Consumer Surveys approach when I was hit by the Panda 4.1 update, which I recovered from on Panda 4.2. I even published my results for all to see over here and it showed, people, my readers, like my short content.
So it really isn't about how short, tall, long or detailed you are. As long as the content satisfies the user, Google should be satisfied too.
Here is the video embed:
Forum discussion at Google+.