This is actually controlled in each individual post.
In the post, there is a tag <-more-> that you can add right where you want your content to cut off. There is actually a little button at the top of the compose window that inserts the tag for you. So for example, if you would like the first paragraph to show on the homepage, put the more tag just below that paragraph in the post. Then when the visitor clicks on the post title or "read more" they will be able to see the entire post.
This topic was started on Feb 28, 2012 and has been closed due to inactivity. If you want to discuss this topic further, please create a new forum topic.