The Internet is only 10 years old, but it has already had a great impact on the world. In its "early" days, it was both heralded as a liberating force for the spread of democracy and condemned as a grave threat to the social fabric. However as the present articles indicate, our knowledge of the Internet across a variety of social science perspectives has now accumulated to where we have a good initial picture of how the Internet really, is (or isn't) affecting social life. One theme stands out: These effects depend on how the unique qualities of Internet communication modes interact with the particular characteristics and goals of the individuals, groups, and communities using them.