I asked a question and answered it myself to help other people, because there was no such question on SO. People got a little bit offended and my question and answer were seriously down-voted to the point that my answer was deleted and I got a score of -7 on my question.
This is the question: https://stackoverflow.com/questions/11158721/sql-not-like-not-working.
My answer was the following one.
I asked in chat if I did anything wrong by asking that question. The trasnscript is here.
Then I answered this question: mysqli_fetch_row() access a specific row in the sql database
My answer was the first among all answers and I got one up-vote.
Later, somebody down-voted my answer. Still a little bit later, my answer was converted into a comment, so I lost the 8 points that I had earned.
My answer was appropriate, considering the information the question contained. There are other answers like this one and this one which consist only of ideas. They were not converted into comments. Mine provided a clear solution.
Is this an act of sabotage? I am not sure? I have never seen this.