tldr; busy.org does not employ youtube's demonetization policies.
It simply does not upvote the same account twice within a given 12 hours interval.
Yesterday I posted a thread with supposedly unsettling / family unfriendly tags and did not get the busy.pay vote:
https://steemit.com/conspiracy-theory/@stimialiti/my-theory-about-why-some-conspiratorial-assassinations-are-sloppy
I wanted to check if it was due to my use of tags, or due to some one thread per day policy, to prevent overposting abuse.
If this thread does not get the busy.pay vote, it will be a hint that some tags are not welcomed by busy.org, because this is my only thread today.
As an aside remark, busy.pay seems to not claim its rewards, which is bad both for its owners and for busy.org users that use the 'busy' tag and get monetized by the busy.pay upvotes.
edit for update:
I guess the answer is that I did not get a second vote yesterday because that was my second thread for yesterday.
Now I got my vote:
https://steemd.com/tx/7468d21eb84318aed5588ef290708a23a1a746cd
And now I got my answer after some digging:
https://steemit.com/busy/@busy.org/introducing-busy-org-the-bot-that-rewards-your-influence
once each 12 hours is the limit.