Gmail: over 7000 mb (and counting) of free web based email space. You can use Google to search through your email!
MyFitnessPal: Free online calorie counter and diet plan. Lose weight by tracking your caloric intake quickly and easily. Find nutrition facts for over 450000 foods. They have apps available for both Android and iPhone, so you can track food and exercise while on the go.
With Google Calendar, you can see your friends' and family's schedules right next to your own; quickly add events mentioned in Gmail conversations or saved in other calendar applications; and add other interesting events that you find online.
Facebook is a social network that allows you to stay connected to friends--old and new.