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.