Further tips about this platform: eventually, people will arrive that we don't particularly care for, but in the spirit of freedom we will allow space for. I recommend first of all not to use your personal timeline for your deeper conversations, but rather groups/pages/forums. Second of all, set the privacy of your own posts to 'friends.' That will prevent people from seeing your posts in the public news feed. Third of all, you do have the ability to block and unblock people. To block them, you browse to their profile page and search for the 'block' option. To unblock them, go to your own profile page's settings and look for the 'blocked users' option.
If you find the public news feed to cluttered, you can always choose from the drop down menu to show only that which you are following.