I've been thinking this recently as well.
You could see the hopium build up in the days leading up to a presumed habbening.
When said habbening fails to appease the crowd
You sit back and wait for the 'I'm done" posts or the 'woe is me I'm angry it's not fair and I'm a lil bitch abt it' posts.
Cross reference the response with known IP's and previous efforts.
You could easily gauge the improvement in overall understanding.
Call it 'growth' if you like.