You forgot to mention that this question is about the article "The Flight from Conversation".
Answer:
With the use of oxymoron, Turkle meant that we live constantly alone, but always in "contact" with the people we care about through technology. This statement influences the entire article showing how this ability is affecting our personal relationships.
Step-by-step explanation:
The article shows how technology has enabled an atificial and shallow form of community. This is because technology allows us to talk to anyone, anywhere in the world, however, this communication does not form bonds and we are always alone.
However, we are alone in a collective way, since all people use this same type of communication. This results in the creation of large groups, which in fact do not exist, are not substantial. As the author of the article says, technology makes us come "a tribe of one."