Default Malware Pop Up - OK

I just visited this forum form my Nexus 5 and a pop up stating that I had malware appeared. It said if I wanted to remove it. I was gonna click 'NO', then I thought "Well, this is xda-developers..." so I... pressed 'YES'.

Nothing happened. Closed the tab and nothing seems to have happened. Did I install malware? Did I get an infection of any kind?

Thanks.