Affiliate Marketing Secrets

I want to work from home with CPA (Cost Per Action) marketing. Generally CPA companies aren’t “get rich quick” scams, but rather advertising networks which allow a website owner to put ads on their website and make money.
They pay every time your website’s visitor clicks on their offers and either enters an e-mail or fills out a survey.
They do require SSN, as do most other affiliate networks.
Suppose that I know what I am doing and I want to put certain ads on my blog to earn money.
Would it be safe to provide my SSN to a company like Blam Ads? How about some other affiliate marketing company?
If it is not safe, then what is the alternative? Many people work for these companies, earning thousands. However, most require SSN in the application. So how do I get hired by one of these businesses without putting myself at risk?
And if this is all a bad idea, then what do I do with my blog?