Also is it wrong for someone else to discuss what a person have talked about before?
Personally, I don't think it is a problem if we discuss something that was already discussed in the past.
I just take a look in one or two boards if is there already an open discussion before I create a new topic. I just look the first page. Alternatively, you can Google the" keywords + bitcointalk " to see if you find something related.
The problem is when people create a new topic when someone already open on the same subject just a few hours before. This generates confusion as nobody follow two discussions. However, for big topics this is most likely happen as there are o many boards and so many people here.
But I wouldn't mind this subject if I were you. Just act normally in the forum and don't spam around, i.e., don't write what you wouldn't say in a normal conversation