Paypal and eBay have to comply with federal tax laws. Uncle Sam wants his cut of any substantial eBay sales, or other money transferred to you. This is called "income", and any significant amount must be taxed. For every extra $1 they can collect in tax, they will be able to spend $5. I wish I could spend the way they do and not end up in jail. Of course, if you don't give them their cut, you could end up in jail.
Paypal must give the government records of your transactions if it is requested of them. Make sure you are filling out a 10-99 if you are getting significant money through paypal.