How to embedd content in articles?

Hi all,

On some site i observed some modules right in the text articles, Those can be links to related posts, article management like print or download, or google adsense.
How are those components integrated right into the text article?

what should i need to edit to be able to display something floating on the right of my text? I see where is located the entry content tag on the single.php page but i don’t know what to do next.

I am wondering if this is sth similar to the image floating on the right of the article à la Typepad (style=”FLOAT: left; MARGIN: 0px 5px 5px 0px) but i would need to insert this in the code directly
Thanks