starting own discussion or replying to other discussion? which is easier?

If you start your own discussions you should be committing yourself to maintaining it by commenting on the responses you get. This is the ONLY way that it can become a discussion (and the only way to make more than a cent or two from it). If you respond to other peoples' discussions, you have no such implied committment, though it is to be hoped that the topic is of sufficient interest that you can have several exchanges of ideas in one discussion. I think, therefore, that responding to good discussions is far more worthwhile than posting discussions simply for the sake of doing so. By all means, start a discussion if you have something to say AND are prepared to discuss the topic. Just posting a topic and then never commenting on it is a waste of time.

I t is easier for me to respond on other discussion already started by other people because you can share your opinion. I am having a hard time starting my own discussion because I can think of anything interesting, I don't know why.

I find it much easier to respond to discussions this is because i find it difficult to think of interesting topics of conversation but other peoples discussions stimulate my thoughts and help me to write.I have started a few discussions but not many of them have been that succesful either due to lack of interest or the time it is uploaded meaning that newer discusions push it to the back i dont know.