This question already has an answer here:
Why does some of the biggest internet companies not use an Extended Validated certificate which makes the address bar would be green and more secure?
I have noticed that Facebook, Google, Amazon the biggest companies I could think of that holds alot of sensitive information does not use EV.
Twitter uses EV, most of the recognized clothing brands like Victoria Secrets does use EV.
The best way I can put this question is in this way:
Why does Twitter use Extended Validated SSL certificate whereas Facebook doesn't
This is a reasonable question because both of these are social networking sites