Lemmy/Fediverse Karma possible?

So I've seen quite a few comments from people regarding the lack of karma so far in Lemmy/The Fediverse, and I was just wondering if because of the nature of how it works if karma is even possible? Although I wouldn't mind too much about it existing, people have made good points about how much it helps moderation and keeps the trolls at bay, so I feel it's a very nice too to have. Thanks in advance for the responses!