I think social currency is quite like stealth gamification already. But yeah that point is a bit nebulous which is why I mentioned the nuances might be hard to grab. All out gamification could end up being something like bejewelled and any 3-match games lol.. If the distribution and frequency of use is commonplace as with the case of content and social interactions, then mass adoption will be quick. One of the reasons again Steem is appealing. Many might not think so because the size of community might not be able to cover all distributions and interactions, which is why niche communities through SMTs might work better.