I'm sorry to say that the Safari web browser for the Mac does not support the use the WYSIWYG* formatting controls when you post. For example, you will not be able to select a word and click on the Bold button and see the word bolded. Instead you'll notice some codes inserted into your editor, however they are not inserted properly and if you post the text it will not look correct.
However, if you are using Mac OS 10 (OS X) there are 2 other Mac browsers that do support the formatting controls. They are Firefox and Camino. Both are very reputable and FREE and can be found at
https://www.mozilla.org/products/
I dont work on a Mac so I can't reccomend one over the other. Perhaps some of you Mac users can chime in on this thread with your comments.
*(What You See Is What You Get)