Not sure how twitter works?

[Blah B]

Ok so if i tweet myself, then those following me will see my tweets on their timeline thing? What if i reply to someones tweet? I want to see my msg show up on their timelime but it doesn't. I also want to be able to see what other people said to the same person, why do i only see the main person's tweets and no responses or anything? Is it a privacy issue? Like i tweet mac miller and don't see my msg show up on his timeline