This text is positioned 0 pixels across and 120 pixels down. Notice that a value of 0 puts the text right up against the edge of the browser window. Also, the image at the top of the page is positioned with a top value of -23, so it's partially cut off by the top of the window.
The browser will position elements on the page regardless of where anything else is. So, if elements happen to overlap, they overlap. That's why the question mark to the left overlaps this text. Once an element is positioned, you can be guaranteed it stays there. Yay!
If your browser doesn't support this CSS property, click here to see what it looks like.