This question might seem a little silly but I was wondering what is the differences between WP.com and WP.org?
I know the main differences like you can’t edit a them file without paying for it, you might get some ads and you get a youname.wordpress.com domain but what are the little features that make the difference.
Think bus vs car. You can ride both, but bus is owned by someone else and what you can do with it is limited.
The best answer is the one directly from the horse’s mouth:
http://en.support.wordpress.com/com-vs-org/
WordPress.com is a hosted blogging service based, of course, on WordPress. You can register and open your blog, choosing from a variety of themes. It’s running the latest version of WordPress.
WordPress.org is the site where you can download WordPress, themes and plugins and install it in your own server.
It’s not easy to answer your question specifically as it’s quite broadly asked. Probably the questions tagged wordpress.com are of use.