This Ask STEPH question comes from another client (whom shall remain nameless until I have cleared it).
Why should I get a WordPress.com account if I have a self hosted WordPress.org site?
If you want your self-hosted WordPress site to be protected from spammy comments, then it is highly recommended that you register for a free WordPress.com account. Registration is free and you do not have to get a WordPress.com blog. You get an API key that you can then use to install the Akismet plugin (which comes pre-installed now on WordPress installs) as well as the link up to the Gravatar site where you can set your icon for when you comment on WordPress sites.