Scrapers can cause a lot of problems for bloggers, mainly because a lot of them remove links back to your blog making it hard for search engines to decide which blog is the copycat.
Here is what Matt Cutts recently said about how best to protect yourself against duplicate content:
If you are syndicating articles on third party sites make sure they link back to the original article on your site, rather than your homepage.
So, having internal links within the post as well as maybe a link to your homepage in your feed footer isn’t going to be the best solution. What you really need is a link to your blog post from within the feed content. Obviously your feed will already have a link to your post anyway but most scrapers tend to remove those links and just keep the title and the content.
Find your feed-rss2.php file in the wp-includes folder and add the following code to line 39 (in WP 2.3.1). The code needs to be added just after where it says <?php the_content() ?>
<p><a href=”<?php the_guid(); ?>”>Permalink + Comments</a></p>
This will make sure search engines know the source of the post and will give your readers an extra place to click to visit your site.