Well, I just found out today that there is now a minimum Effective Steempower Requirement when you choose to sell your upvotes through one of the most popular vote-selling service on Steem, SmartSteem.
It seems that only accounts with an effective Steem Power of at least 100 is able to sell their votes and thus earn some token in return.
I for one is actually pleased to hear this new change. If it was me though I would have set the minimum to at least 500 SP (or minnow level) to somewhat forced the 99% of users to interact more with the community (if my memory serves me right, someone made a post months ago detailing how 99% of users on Steem have an SP less than 500).
According to PenguinPablo's daily Steem Stats, it seems the number of daily posts including comments is now around 60-70k daily. But for some reason I think that 85% of those posts are comments coming from bots and from some random curation groups. XD
As for me, I have already stopped using bidbots or any upvote subscription services for over 6 months now but in case some of you are still wondering why your alt acccounts with less than 100SP have now stopped upvoting, maybe this is the answer you are looking for. XDv