Anything with position: fixed is taken out of the normal content flow and, therefore, does not take up space on the page. If I understand you correctly, you want your menu (which is position: fixed) to take up space on the page but to remain floating. To accommodate this, you will need to do one of two things:
- If you are OK with simply making room for the menu down the entire vertical length of the page, just add a margin-right to the entire page that is the width (or slightly wider) than the menu.
- If you want to have each article have a space in the upper-right of it's content just big enough for the menu and for the content to flow around it, create a div that is the same size as the menu before each article and give it float: right.
Your question was somewhat vague as to the outcome that you were looking for and without the code I cannot give specifics. I hope this gives a general guide as to where to go.