SunnyGirl, you have it 100% correct
(the last two that you quoted anyway)
The reason the forum forces you to quote some context from the previous message is for people that read your posts not using dogbanter.com (e.g. through a newsreader).
When you are reading a thread in this forum, it logically sorts each message one under the other so it makes sense, but that is not always the case with a newsreader, so not quoting can (not always) cause problems for newsreaders.
The reason that your posts look different is that the people that have replied to you have used a newsreader to reply, and the reason I am not quoting your message in this reply is that this specific forum (About DogBanter) does not go outside of this forum, so there is no need.
I am currently rewriting parts of the newsgroup interface, and will look at a way to make it less 'clunky' and easier to use, but it will be a while until I am able to release something...
I hope this makes some sense