Since I don't know what "these" refers to here, I will just assume that the question addresses social networks generally.
Some impacts are:
Positive
-better information
-security (you can mark people safe during Earthquake)
-faster contact with peopl
-possibility of forming groups
-additional communication platform
Negative:
-less privacy
-lack of control over data
-being able to spy on people
-being able to find things from the past
-bosses spying on their workers
Answer:
Social practices shape everyday life and are familiar to all members of the community, even if not everybody participates in them. Distinctive social practices that are specially relevant to a community and help reinforce a sense of identity and continuity with the past are given priority.
Author of British and American Manufacturing Productivity: A Comparison and Interpretation. Productivity, in economics, the ratio of what is produced to what is required to produce it. Usually this ratio is in the form of an average, expressing the total output of some category of goods divided by the total input of, say, labour or raw materials.