On the project I'm working on (Q&A platform), we're trying to get users to spend more time on their answers. We want to encourage longer form helpful replies, rather then spur of the moment short replies. I've seen a lot of examples of how UI can drive shorter input, for example...
Twitter clients have a small overlay box pop-up when composing a tweet. I feel this encourages the user to tweet more often as they're still in the app and the UI is micro so funnels the user to create short, snappy (mostly inane) tweets. Obviously the character limit is a physical barrier when actually composing, but the UI is very much focused on short, rapid content.
After the launch of gmails new compose view a few weeks ago I feel my emails have become much shorter and I tend to send more. This simple change from composing an email in a new page to composing one in the same window seems to have had a significant change in my behaviour. I also feel the editing options being stripped away from the UI now creates less friction in sending email. I'm unsure if this is a negative or not yet.
...but not many examples of the opposite. The ultimate long form content creation seems to be pen and paper; a whole A4 page to use and each word took time to curate.
Is there any research surrounding this subject and how can you encourage longer, more thoughtful replies?