Voting on comments (up-vote & down-vote) is still free on Twpter, however in order to be eligible to vote on comments, you must have a balance of at least 200 (Tc) when you log in.
If your balance falls below 200 (Tc) during your user session, you will still be able to vote until you log out of that user session. However, the next time you log in (thereby creating a new user session) you will not be able to vote until you replenish your credits to over the 200 (Tc) minimum by making a monetary donation.
This is being done for the benefit of members who are actually donating to the platform, and for limiting the influence of those who do not donate.
Remember: Twpter.com does not accept any paid advertising (or 3rd party funding) for income and relies solely on donations from members to meet operating expenses. It is only fair that users who support our platform with donations should have the right to vote.
We disabled the comment display on the old comment test pages that were a vestige of the static page commenting platform (which was to be the original scope of this project) due to looping error generation issues that were causing our server to hang while logging these looping error messages.
However, these pages were archived by the "Wayback Machine" here: