As your site starts to receive traffic, so it automatically receives hits from auto-bots. These are programs acting as real people, leaving innocent looking comments on your posts. Once you accept one of the comments from them, they are then authorised to leave untold others, which generally tend to be link after link of spam.
To protect yourself from this plague, you need to do the following.
1. Create and activate an account at WordPress.com (this is totally different to the wordpress associated with your website).
2. Create and activate an account with Akismet. Follow the steps to acquire your Akismet key. If you are familiar with plug ins on your site, then go to the already installed plug in and activate it using your key. Alternatively, once you get the email containing your key forward it to us and we will set it up for you.
Until you follow the above instructions, you WILL get untold message after message, comment after comment from what look like genuine people leaving you kind words about what a wonderful site you have.