How can a web site know my number?

Hi I just downloaded dolphin & surfing. Then I click on a porn site link. (xxxxxxxx if I remember correctly).
Then I receive 2 text! relating to porn stuff!
How could it know my phone number & send text to me!!!!?
Is it the browser or what?
Is it normal? Am I being infected with malware/**wares?

Sorry for my bad english

 

Thanks for the reply. But I'm aware of these permissions.
But not sure which app is causing.
I guess it's the browser but permissions needed are only:

Location
Browser history/bookmarks
Network
Storage
System tools-to prevent phone from sleeping

I'm using custom ROM. Does that matter?
Perhaps the safest is official ROM?

 

I don't use mobile phone to surf porn site at all.
Because someone said I could play flash on galaxy ace, I am just trying out!

 

Ok thanks all of you.
I think I found out.
I went to site again and read terms.
It said just clicking preview will send sms (with $ charge). I've un-subscribed...
should be my carrier. I suspect.

You mean it's not as secure as default browser?
Which browser offer good security and functionality (like dolphin)?
tab browsing, gesture, etc looks cool! (I can't use firefox on galaxy ace).
Any pointers would be helpful.