Any company that creates 4.5 million jobs is great for the economy. In the aftermath of the Great Recession, they have to be given credit for encouraging our economy with jobs that pay taxes, drive consumption, and create other jobs. They should also be given credit for changing their business model to create jobs.
When a company creates jobs on a local level, national level and even an international level, that company is doing the economic system justice. By providing jobs, this helps the cycle stay healthy for the consumers and the businesses in the short and long run. Facebook has created 4.5 million jobs; that is a tremendous plus for the economy. It has created the necessary growth while providing a very popular service.
Yes, Facebook is good for the economy, because it helps people who want to buy and sell certain goods find each other. That removes an inefficiency of lack of information that exists in a capitalist system. I am not sure how Facebook created 4.5 million jobs, but if Facebook helps people find people who need jobs, that is a good thing for the economy.
Although Facebook may have created a large number of jobs, the actually productive lost due to people wasting their days away at work and home, doing things on Facebook, is hard to calculate. If anything the actual job gains provided by Facebook are netted out by the productivity loss by those addicted to it.