You can now have the system ignore posts by users you select. To do so, go to any post by that user on the website. Click or hover on their username and select "Ignore"
You'll be then asked to confirm it.
That will add that user to your ignore list. When you are done you can just close the window or go elsewhere on the site.
When that person posts you will see a short note saying that they have posted and you have chosen to ignore their postings.
Marking someone as a "Buddy" works the same way. When a "Buddy" posts you will be sent an individual email of their post. Their post will also be included in your Digest if you are subscribed for that category or thread.