Duplicate content is kind of a nightmare to many blog owners and many a times it is the blog owner themselves who are responsible for creating this mess. The homepage is the most important part of a website and hence it is important that it does not add to duplication.
What is Duplicate content?
In simple words the content of a single post should be displayed in full only on a single URL location. If you use the full content on multiple locations or on different URL’s you are duplicating the content.
Search engines do not like duplications and if they find your website duplicating content they will penalize the website (Duplicate Penalty). Therefore it is important that first you understand what duplicate content is and avoid the same.
Generally on the homepage you can use the post excerpts which are just a summary or a teaser of the full post with a link to the single post with full content. So when a user visits the homepage they can read the excerpts and click the links to read the rest of the story. Search engines have no problem with this technique and are widely accepted. Matt Cutts video (below) confirms it.
There are certain pages that keep updating regularly like the homepage, category, author and tag pages. Usually category, tag and author pages may again lead to duplication hence it is important to use noindex meta tag on pages that search engines might consider duplicate. For SEO purpose I have the homepage, individual posts, and category pages as index-able and other pages like tags and author page are set as noindex.
Search engine bots will frequently visit the pages that update often like the homepage and the category pages it is there, where they find new content and when you use excerpt they know that the full article is at the provided link. If you use the full article on the homepage as well as have a link to the full article (which really does not make sense), search engine will see this as duplicate content.
So make sure you use post excerpts on homepage and avoid using full content for better SEO.