I disagree with most of that.
SOME businesses will look at things such as facebook.
Businesses can't view any facebook no matter what. Not to mention that there is an immediate issue with privacy legislation, but if I applied for a job with a company based in the USA, they can't see my profile because there are no common networks. Even Australian businesses can't see me unless they are a part of my university network
They aren't screwing you, the information is made public the moment you allow it to be. If you don't want people or companies seeing shit that is controversial, then don't put it up there in the first place.
In reality, large firms are the ones with the resources and budgets to warrant having their HR department look into things such as facebook for job candidates. There is nothing wrong with social networking as far as employment goes, but I strongly believe that if you have a solid chance at working for one of the large companies that are likely to investigate things like this, then you would generally be a person that is smart enough not to have controversial content on your profile in the first place.