PayPal adopts eBay as a key platform to grow its userbase , because of the need for an online payment system on eBay .
The combined entity , initially called X.com , later changes its name to PayPal .
PayPal adopts eBay as a key platform to grow PayPal 's userbase , because of the need for an online payment system on eBay .
The combined entity , initially called X.com , later changes its name to PayPal .