My Profile is a short biography about yourself. It tells the reader your age, gender, education, and any other basic information about you. Anytime you update that information, it will appear in the news and feeds og all your friends.
Notes and posted items is a cross between simple notes and daily blog entries. The possibilities are nearly endless. You can post HTML videos, photos (which you can also tag your friends in). You can also blog a post about events and certain clubs.
Albums are exactly that, albums. You can upload photos on your Facebook and post them for all to see, and then revisit event later on. You can also tag your friends in these photos so that they too can see themselves in the newsfeed.
Events is a particularly useful tool for planners. It gives people the oppurtunity of inviting a mass number of people to a event and getting almost an instant response if the will be attending or not. Event look similar to regular profiles except for a few differences in the layout and the attending option.