Facebook has improved my life as well.

I went to high school in one city, college in one 1,000 miles away. Have since worked in cities all over the world. I don't know how I would manage to keep even a tenuous grasp on all the connections I have with people in these different places without Facebook. Admittedly, these are not and never will be deep social bonds I am maintaing, but that is hardly the point. There is value in maintaining a large web of shallow social connections. Facebook helps me do this.

Moreover, whether or not Facebook has improved the life of me or anyone I care about is irrelevant to an objective evaluation of the site's value. I could make the same case for anti-malaria drugs.