There are numerous Spam fighting mechanisms, but the easiest and probably best to get started is Akismit. It is free for Personal use. Even if you think you want to become a commercial site at some point, go ahead and register as a Personal account and get your spam blocking on. They make it easy to upgrade when you BECOME ready. I would also argue that to be something beyond Personal you would have to be a) selling something b) operating the site under a business or LLC, or b) making more money than your hosting costs from ad-revenue or similar mechanism. At a quick glance I could not find any helpful clarifications on the website. Commercial plans start at $5 a month.
Other Spam Plugins can be found here: Dreamhost Wiki Article – SPAM
Steps to enabling Akismet:
- Log-in to your WordPress site
- If it is not pre-installed (Dreamhost 1-Click WordPress install will have installed the Plugin), on the left menu bar go to Plugins > Add New. Repeat the process from the first section of: Finding/Installing a Plugin
- Go to Askismet
- Signup for a WordPress.com account, if you do not already have one. Links will be on the Akismet page.
- Subscribe to a plan. The Askismet page will walk you through the process
- Get the your Activation Code
- Go to Plugins > Installed Plugins
- Select Activate Plugin
- Go to the Settings (Link will be where the Activate was previously) and enter your activation code. SAVE CHANGES.
- Pat yourself on the back you are done.
Now that you are finished you should get a lot less offers for the most random things the internet can think up.