Remember that when you post a message, by default the line breaks and spaces are not preserved.
If you want to have them preserved (in particular when posting tabular data) you need to enter a few HTML tags: enclose the section which you don't want reformated between the tags [pre] and [/pre] If you do so, please don't forget the last tag, otherwise the following messages will be messed up.
To create a new paragraph, just use the tag
Another point is that due a software problem, the last line of your message might end up truncated. I don't have a simple solution for that. I recommend you just end your message by a blank line.