A log. Each member signing into chat gets logged in on chain as well if your service writes a comment with beneficiary going to that account holder. Incoming votes on your frontend would be a vote for that comment on chain. So rather than voting in chat like one would if they "liked" something, people would vote for the account name which is just a comment behind the scenes on chain. Mitigates the risk of token farming as well since it can be monitored. Your service would only need to publish one post, then place those comments under it forever. The comments don't have to say anything. Just a placeholder. Chat login would have to expire every 24 hours so a new comment gets written for maximum rewards efficiency. Keep in mind I'm just pulling this idea out of thin air. No clue how you'd go about doing that. Maybe @acidyo would be interested in picking this apart. I don't know a damn thing about the technical side or if that would be a feasible solution.

People wouldn't be able to vote for one individual in chat numerous times in one day, so the voting or tipping with votes in chat would be used sparingly.

Logging in and logging out shouldn't trigger a new comment on chain. Just one every 24 hours or something more suitable.