After having setup more than 3 dozen WordPress sites, I know very well what a pain it can be to go through and populate the site with test data. You have to go in and manually create 5-10 posts, several pages, perhaps some portfolio items in a custom post types, and more. It takes forever.
Well, forget about doing that. The Duplicate Posts Plugin by lopo is one of the single great plugins I have ever used. Not because it provides a huge array of functionality, or dozens and dozens of features, but because it does one thing, and does it very, very well.
The plugin is designed to give you a really easy way to duplicate an already-written post and copy it over to a new post. So, instead of writing 5-10 posts by hand, you write one, then duplicate it 5-10 times.
It has been designed to fit seamlessly into the WordPress interface by adding “Duplicate” and “Copy to new draft” links on the posts list and post editor screens.
Not only does the plugin copy over post content, it also does tags, categories, custom fields, featured images, everything.
I have not setup a single WordPress site since I discovered this plugin without installing it.